English plural

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English grammar series
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In the English language, nouns are inflected for grammatical number —that is, singular or plural. This article discusses the variety of ways in which English plurals are formed for nouns. For the plurals of pronouns, see English personal pronouns.

Phonetic transcriptions provided in this article are for Received Pronunciation and General American.

Contents 1 Regular plurals 2 Almost-regular plurals 3 Irregular plurals 3.1 Nouns with identical singular and plural 3.2 Irregular -(e)n plurals 3.3 Ablaut plurals 3.4 Irregular plurals from Latin and Greek 3.5 Irregular plurals from other languages 3.6 Words better known in the plural 4 Plurals of numbers 5 Nouns used attributively 6 Defective nouns 7 Plurals of compound nouns 7.1 Compounds from the French 8 Plurals (and singulars) of headless nouns 8.1 Related collective nouns 9 Nouns with multiple plurals 10 Plurals of symbols and initialisms 11 Plural to singular by back-formation 12 Place names 13 Plurals of names of peoples 14 Discretionary plurals 15 Snob plurals 16 See also 17 References 18 External links

[edit] Regular plurals

The plural morpheme in English is suffixed to the end of most nouns. Regular English plurals fall into three classes, depending upon the sound that ends the singular form:

Where a singular noun ends in a sibilant sound —/s/, /z/, /ʃ/, /ʒ/, /tʃ/ or /dʒ/— the plural is formed by adding /ɨz/. The spelling adds -s, or -es if the singular already ends in -s:

kiss	kisses	/ˈkɪsɨz/
phase	phases	/ˈfeɪzɨz/
dish	dishes	/ˈdɪʃɨz/
massage	massages	/məˈsɑːʒɨz/ or /ˈmæsɑːʒɨz/
witch	witches	/ˈwɪtʃɨz/
judge	judges	/ˈdʒʌdʒɨz/

When the singular form ends in a voiceless consonant (other than a sibilant) —/p/, /t/, /k/, /f/ or /θ/— the plural is formed by adding /s/. The spelling adds -s:

lap	laps	/læps/
cat	cats	/kæts/
clock	clocks	/klɒks/
cuff	cuffs	/kʌfs/
death	deaths	/dɛθs/

For all other words (i.e. words ending in vowels or voiced non-sibilants) the regular plural adds /z/, represented orthographically by -s:

boy	boys	/bɔɪz/
girl	girls	/ɡɜrlz/
chair	chairs	/tʃɛərz/

Morphophonetically, these rules are sufficient to describe most English plurals. However, there are several complications introduced in spelling.

The -oes rule: most nouns ending in o preceded by a consonant also form their plurals by adding -es (pronounced /z/):

hero	heroes
potato	potatoes
volcano	volcanoes or volcanos

The -ies rule: nouns ending in a y preceded by a consonant usually drop the y and add -ies (pronounced /iz/). This is taught to many North American and British students with the mnemonic: Change the y to i and add es:

cherry	cherries
lady	ladies

However, proper nouns (particularly those for people or places) ending in a y preceded by a consonant form their plurals regularly:^[1][2]

Germany	Germanys (as in The two Germanys were unified in 1990; this rule is commonly not adhered to as several book titles show;[3][4] Sicilies and Scillies, rather than Sicilys and Scillys, are the standard plurals of Sicily and Scilly.)
Harry	Harrys (as in There are three Harrys in our office)

The rule does not apply to words that are merely capitalized common nouns:

P&O Ferries (from ferry)

Other exceptions include lay-bys and stand-bys.

Words ending in a y preceded by a vowel form their plurals regularly:

day	days
monkey	monkeys

(Money/Monies is an exception, but money can also form its plural regularly.^[5])

[edit] Almost-regular plurals

Many nouns of foreign origin, including almost all Italian loanwords, are exceptions to the -oes rule:

canto	cantos
homo	homos
photo	photos
zero	zeros
piano	pianos
portico	porticos
pro	pros
quarto (paper size)	quartos
kimono	kimonos

In Old and Middle English voiceless fricatives /f/, /θ/ mutated to voiced fricatives before a voiced ending.^[6] In some words this voicing survives in the modern English plural. In the case of /f/ changing to /v/, the mutation is indicated in the orthography as well; also, a silent e is added in this case if the singular does not already end with -e:

bath	baths	/bɑːðz/, /bæðz/
mouth2	mouths	/maʊðz/
calf	calves	/kɑːvz/, /kævz/
leaf1	leaves (see footnote), /liːvz/
knife2	knives	/naɪvz/
life	lives

In addition, there is one word where /s/ is voiced in the plural:^[6]

house2

houses

/haʊzɨz/

Many nouns ending in /f/ or /θ/ (including all words where /f/ is represented orthographically by gh or ph) nevertheless retain the voiceless consonant:

moth	moths (voiced /mɒðz/ is rare but does occur in New England and Canada)
proof	proofs

Some can do either:

dwarf3	dwarfs/dwarves
hoof	hoofs/hooves
elf	elfs/elves
roof	roofs (commonly voiced as /ruːvz/ to rhyme with hooves, but rooves is a rare archaic spelling)
staff4	staffs/staves
turf	turfs/turves (latter rare)

^ Note 1: The Toronto Maple Leafs ice hockey team is a special case. (See the collective nouns section below.)

^ Note 2: In a Canadian accent, the mutation to a voiced consonant produces a change in the sound of the preceding diphthong (/aʊ/ or /aɪ/).

^ Note 3: For dwarf, the common form of the plural was dwarfs —as, for example, in Walt Disney's Snow White and the Seven Dwarfs— until J. R. R. Tolkien popularized dwarves; he intended the changed spelling to differentiate the dwarf fantasy race in his novels from the cuter and simpler beings common in fairy tales, but his usage has since spread. Multiple astronomical dwarf stars and multiple nonmythological short human beings, however, remain dwarfs.

^ Note 4: For staff (/stæf/ or /stɑːf/) in the sense of a body of employees, the plural is always staff; otherwise, both staffs and staves (/steɪvz/) are acceptable, except in compounds, such as flagstaffs. Staves is rare in North America except in the sense of magic rod, or the musical notation tool; stave of a barrel or cask is a back-formation from staves, which is its plural. (See the Plural to singular by back-formation section below.)

[edit] Irregular plurals

There are many other less regular ways of forming plurals, usually stemming from older forms of English or from foreign borrowings.

[edit] Nouns with identical singular and plural

Some nouns spell their singular and plural exactly alike; some linguists regard these as regular plurals. Many of these are the names of animals:

deer

moose

sheep

bison

salmon

pike

trout

fish

swine

The plural deers is listed in some dictionaries.^[7] As a general rule, game or other animals are often referred to in the singular for the plural in a sporting context: He shot six brace of pheasant, Carruthers bagged a dozen tiger last year, whereas in another context such as zoology or tourism the regular plural would be used. Similarly, nearly all kinds of fish have no separate plural form (though there are exceptions -- such as rays, sharks or lampreys). And the word fish itself is also troublesome, being generally used as a plural when in the context of food, but forming a regular plural otherwise (thus three lots of fish and chips, the industry landed 5,200 tonnes of fish in 1998 but the order of fishes, the miracle of the loaves and fishes, the phrase sleep with the fishes). The usage does vary, however, so that for example the phrase five fish in an aquarium might to another native user be five fishes in an aquarium. Using the plural form fish could imply many individual fish(es) of the same species while fishes could imply many individual fish(es) of differing species.

Other nouns that have identical singular and plural forms include:

aircraft; watercraft; spacecraft; hovercraft; ocean-going craft

information (always used with singular verbs)

the blues⁴

cannon (sometimes cannons)

head⁵

stone (occasionally stones)⁶

^ Note 4: Referring to individual songs in the blues musical style: play me a blues; he sang three blues and a calypso

^ Note 5: Referring, in the plural, to animals in a herd: fifty head of cattle

^ Note 6: As a unit of weight equal to 14 pounds

[edit] Irregular -(e)n plurals

The plural of a few nouns can also be formed from the singular by adding -n or -en, stemming from the Old English weak declension:

ox	oxen	(particularly when referring to a team of draft animals, sometimes oxes in nonstandard American English)
child	children	(actually earlier plural cildra/cildru plus -en suffix, forming a double plural)
brother	brethren	(archaic plural of brother; earlier brether plus -en suffix, forming a double plural. Now used in fraternal orders.)
cow	kine	(archaic/regional; actually earlier plural kye [cf. Scots kye - cows] plus -en suffix, forming a double plural)
eye	eyen	(rare, found in some regional dialects)
shoe	shoon	(rare/dialectal)
house	housen	(rare/dialectal, used by Rudyard Kipling in Puck of Pook's Hill)
hose	hosen	(rare/archaic, used in King James Version of the Bible)

The word box, referring to a computer, is pluralized semi-humorously to boxen in the Leet dialect. Multiple VAX computers, likewise, are sometimes called Vaxen particularly if operating as a cluster, but multiple Unix systems are usually Unices along the Latin model.^[8]

The word sistren, referring to Christian sisters [modeled on brethren], is also semi-humorously pluralized.^{[citation needed]}

[edit] Ablaut plurals

The plural is sometimes formed by simply changing the vowel sound of the singular, in a process called ablaut (these are sometimes called mutated plurals):

foot	feet
goose	geese
louse	lice
man	men
mouse	mice
tooth	teeth
woman	women

This group consists of words that historically belong to the Old English consonantal declension, see Germanic umlaut#I-mutation in Old English.

Mouse is sometimes pluralized mouses in discussions of the computer mouse; however, mice is just as common.

Mongoose has the plural mongooses, or less commonly mongeese by analogy to geese.

[edit] Irregular plurals from Latin and Greek

English has borrowed a great many words from Latin and Classical Greek. The general trend with loanwords is toward what is called Anglicization or naturalization, that is, the re-formation of the word and its inflections as normal English words. Many nouns (particularly ones from Latin) have retained their original plurals for some time after they are introduced. Other nouns have become Anglicized, taking on the normal s ending. In some cases, both forms are still competing.

The choice of a form can often depend on context: for a linguist, the plural of appendix is appendices (following the original language); for physicians, however, the plural of appendix is appendixes. Likewise, a radio or radar engineer works with antennas, but an entomologist deals with antennae. The choice of form can also depend on the level of discourse: traditional Latin plurals are found more often in academic and scientific contexts, whereas in daily speech the Anglicized forms are more common. In the following table, the Latin plurals are listed, together with the Anglicized forms when these are more common.

• Final a becomes -ae (also -æ), or just adds -s:

alumna	alumnae
formula	formulae/formulas
encyclopaedia (or encyclopædia) / encyclopedia	encyclopaedias / encyclopedias (encyclopaediae and encyclopediae are rare)

• Final ex or ix becomes -ices (pronounced /ɨsiːz/), or just adds -es:

index	indices	/ˈɪndɨsiːz/	or indexes
matrix	matrices	/ˈmeɪtrɨsiːz/
vertex	vertices	/ˈvɜrtɨsiːz/

Some people treat process as if it belonged to this class, pronouncing processes /ˈprɒsɨsiːz/ instead of standard /ˈprɒsɛsɨz/. Since the word comes from Latin processus, whose plural in the fourth declension is processūs with a long u, this pronunciation is by analogy, not etymology.

• Final is becomes es (pronounced /iːz/):

axis	axes	/ˈæksiːz/
crisis	crises	/ˈkraɪsiːz/
testis	testes	/ˈtɛstiːz/

Axes, the plural of axis, is pronounced differently^{[clarification needed]} from axes (/ˈæksɨz/), the plural of ax(e).

• Final ies remains unchanged:

series	series
species	species

• Final on becomes -a:

automaton	automata
criterion	criteria
phenomenon	phenomena (more below)
polyhedron	polyhedra

• Final um becomes -a, or just adds -s:

addendum	addenda
agendum (obsolete, not listed in most dictionaries)	agenda means a list of items of business at a meeting and has the plural agendas
datum	data (Now usually treated as a singular mass noun in both informal and educated usage, but usage in scientific publications shows a strong American/British divide. American usage generally prefers to treat data as a singular in all contexts, including in serious and academic publishing.[9][10][11] British usage now widely accepts treating data as singular in standard English,[12] including educated everyday usage[13] at least in non-scientific use.[14] British scientific publishing usually still prefers treating data as a plural.[15] Some British university style guides recommend using data for both the singular and the plural use[16] and some recommend treating it only as a singular in connection with computers.[17]) In engineering, drafting, surveying, and geodesy, and in weight and balance calculations for aircraft, a datum (plural datums or data) is a reference point, surface, or axis on an object or the Earth's surface against which measurements are made.
spectrum	spectra (as in power spectrum in electrical engineering)
forum	fora/forums
medium	media (in communication systems and digital computers. This is now often treated as a singular mass noun)/ mediums (spiritualists, or items of medium size)
corrigendum	corrigenda
memorandum	memoranda/memorandums
millennium	millennia

• Final us becomes -i (second declension, [aɪ]) or -era or -ora (third declension), or just adds -es (especially in fourth declension, where it would otherwise be the same as the singular):

alumnus	alumni
corpus	corpora
census	censuses
focus	foci
genus	genera
prospectus	prospectuses (plural prospectus is rare although technically correct)
radius	radii
syllabus	syllabi/syllabuses (in fact the Latin plural is syllabūs)
viscus	viscera
virus	viruses/virii ( see Plural form of words ending in -us#Virus )

cactus	cactuses/cacti (in Arizona many people avoid either choice with cactus as both singular and plural.)
fungus	fungi
hippopotamus	hippopotamuses/hippopotami
octopus	octopuses (note: octopi also occurs, although it is strictly speaking unfounded,[18] because it is not a Latin noun of the second declension, but rather a Latinized form of Greek ὀκτώ-πους, eight-foot. The theoretically correct form octopodes is rarely used.)
platypus	platypuses (same as octopus: platypi occurs but is etymologically incorrect, and platypodes, while technically correct, is even rarer than octopodes)
terminus	termini/terminuses
uterus	uteri/uteruses

• Final us remains unchanged in the plural (fourth declension - the plural has a long ū to differentiate it from the singular short ǔ):

meatus	meatus
status	status

Colloquial usages based in a humorous fashion on the second declension include Elvii to refer to multiple Elvis impersonators and Loti, used by petrolheads to refer to Lotus automobiles in the plural.

• Final as in one case of a noun of Greek origin changes to -antes:

Atlas	Atlantes (statues of the hero); but
atlas	atlases (map collections)

• Final ma in nouns of Greek origin can add -ta, although -s is usually also acceptable, and in many cases more common.

stigma	stigmata/stigmas
stoma	stomata/stomas
schema	schemata/schemas
dogma	dogmata/dogmas
lemma	lemmata/lemmas
anathema	anathemata/anathemas

[edit] Irregular plurals from other languages

• Some nouns of French origin add an -x, which may be silent or pronounced /z/:

beau	beaux or beaus
bureau	bureaus or bureaux
château	châteaux or châteaus
tableau	tableaux or tableaus

Foreign terms may take native plural forms, especially when the user is addressing an audience familiar with the language. In such cases, the conventionally formed English plural may sound awkward or be confusing.

• Nouns of Slavic origin add -a or -i according to native rules, or just -s:

kniazhestvo	kniazhestva/kniazhestvos
kobzar	kobzari/kobzars
oblast	oblasti/oblasts

• Nouns of Hebrew origin add -im or -ot (generally m/f) according to native rules, or just -s:

cherub	cherubim/cherubs
seraph	seraphim/seraphs
matzah	matzot/matzahs
kibbutz	kibbutzim/kibbutzes

Ot is pronounced os (with unvoiced s) in the Ashkenazi dialect.

• Many nouns of Japanese origin have no plural form and do not change:

benshi	benshi
otaku	otaku
samurai	samurai

Other nouns such as kimonos, ninjas, futons, and tsunamis are more often seen with a regular English plural. However, there are nouns such as mawashi that are seen with an irregular plural: mawashia.

• In New Zealand English, nouns of Māori origin can either take an -s or have no separate plural form. Words more connected to Māori culture and used in that context tend to retain the same form, while names of flora and fauna may or may not take an -s, depending on context. Many regard omission as more correct:

kiwi7	kiwi/kiwis
kowhai	kowhai/kowhais
Māori8	Māori/(occasionally Māoris)
marae	marae
tui	tuis/tui
waka	waka

^ Note 7: When referring to the bird, kiwi may or may not take an -s; when used as an informal term for a New Zealander, it always takes an -s.

^ Note 8: Māori, when referring to a person of that ethnicity, does not usually take an -s. Many speakers avoid the use of Māori as a noun, and instead use it only as an adjective.

• In Canada and Alaska, some words borrowed from Inuktitut retain traditional plurals (see also Plurals of names of peoples, below):

Inuk	Inuit
inukshuk	inukshuit

• Nouns from languages other than the above generally form plurals as if they were native English words:

canoe	canoes
cwm	cwms (Welsh valley)
igloo	igloos
kangaroo	kangaroos
kayak	kayaks
kindergarten	kindergartens
pizza	pizzas
sauna	saunas
ninja	ninjas

[edit] Words better known in the plural

Some words of foreign origin are much better known in the plural; usage of the original singular may be considered pedantic or actually incorrect or worse^[19] by some speakers. In common usage, the original plural is considered to be the singular form. In many cases, back-formation has produced a regularized plural.

Original singular	Original plural/ common singular	Common plural
agendum	agenda9	agendas
alga	algae	algae
bacterium	bacteria	bacteria
biscotto	biscotti	biscotti
candelabrum	candelabra	candelabras
datum10	data	data (mass noun)
graffito	graffiti	graffiti (mass noun)
insigne	insignia	insignias
opus	opera	operas
panino	panini	paninis (currently gaining use)
paparazzo	paparazzi	paparazzi
spaghetto	spaghetti	spaghetti

^ Note 9: An agenda commonly is used to mean a list of agendum.

^ Note 10: A single piece of data is sometimes referred to as a data point. In engineering, drafting, surveying, and geodesy, and in weight and balance calculations for aircraft, a datum (plural datums or data) is a reference point, surface, or axis on an object or the earth’s surface against which measurements are made.

Some plural nouns are used as such —invariably being accompanied by a plural verb form— while their singular forms are rarely encountered:

nuptial	nuptials
phalanx11	phalanges
tiding	tidings
victual	victuals
viscus	viscera

^ Note 11: In medical terminology, a phalanx is any bone of the finger or toe. A military phalanx is pluralized phalanxes.

A related phenomenon is the confusion of a foreign plural for its singular form:

criterion	criteria
phenomenon	phenomena
consortium	consortia
symposium	symposia

Magazine was derived from Arabic via French. It was originally plural, but in French and English, it is always regarded as singular.

[edit] Plurals of numbers

English, like some other languages, treats large numerals as nouns (cf. there were ten soldiers and there were a hundred soldiers). Thus, dozens is preferred to tens, while hundreds and thousands are also completely acceptable.

Plurals of numbers differ according to how they are used. The following rules apply to dozen, score, hundred, thousand, million, and similar terms:

• When modified by a number, the plural is not inflected, that is, has no -s added. Hence one hundred, two hundred, etc. For vaguer large numbers, one may indifferently say several hundred or several hundreds.
• When used alone, or followed by a prepositional phrase, the plural is inflected: dozens of complaints, scores of people. However, either complaints by the dozen or complaints by the dozens is acceptable (although differing in meaning).
• The preposition of is used when speaking of nonspecific items identified by pronouns: two hundred of these, three dozen of those. The of is not used for a number of specific items: three hundred oscilloscopes. However, if the pronoun is included with the specific item, the of is used: five million of those dollar bills.

A sagan of any kind of items is at least four billion, as in billions and billions. Hence, about a sagan of micrometeorites. ^[20][21]

[edit] Nouns used attributively

Nouns used attributively to qualify other nouns are generally in the singular, even though for example, a dog catcher catches more than one dog, and a department store has more than one department. This is true even for some binary nouns where the singular form is not found in isolation, such as a trouser mangle or the scissor kick. This is also true where the attribute noun is itself qualified with a number, such as a twenty-dollar bill, a ten-foot pole or a two-man tent. The plural is used for pluralia tantum nouns: a glasses case is for eyeglasses, while a glass case is made of glass (but compare eyeglass case); also an arms race versus arm wrestling. The plural may be used to emphasise the plurality of the attribute, especially in British English but very rarely in American English: a careers advisor, a languages expert. The plural is also more common with irregular plurals for various attributions: women killers are women who kill, whereas woman killers are those who kill women.

[edit] Defective nouns

Some nouns have no singular form. Such a noun is called a plurale tantum (see also Words better known in the plural above):

cattle, billiards, clothes, measles, news, thanks

Some of these do have singular adjective forms, such as billiard ball. In addition, some are treated as singular in certain sentences, e.g., billiards is a game played on a table with billiard balls and a cue, measles is an infectious disease. Thanks is usually treated as a plural. Although cow is sometimes used in colloquial English for cattle, the term is age and gender specific.

A particular set of nouns, describing things having two parts, comprises the major group of pluralia tantum in modern English:

glasses (a pair of spectacles), pants, panties, pantyhose, pliers, scissors, shorts, suspenders, tongs (metalworking & cooking), trousers, etc.

These words are interchangeable with a pair of scissors, a pair of trousers, and so forth. In the American fashion industry it is common to refer to a single pair of pants as a pant —though this is a back-formation, the English word (deriving from the French pantalon) was originally singular. In the same field, one half of a pair of scissors separated from the other half is, rather illogically, referred to as a half-scissor. Tweezers used to be part of this group, but tweezer has come into common usage only since the second half of the twentieth century.

Mass nouns (or uncountable nouns) do not represent distinct objects, so the singular and plural semantics do not apply in the same way. Some examples:

• Abstract nouns

deceit, information, cunning, and nouns derived from adjectives, such as honesty, wisdom, beauty, intelligence, poverty, stupidity, curiosity, and words ending with ness, such as goodness, freshness, laziness, and nouns which are homonyms of adjectives with a similar meaning, such as good, bad (can also use goodness and badness), hot, and cold.

• In the arts and sciences

chemistry, geometry, surgery, the blues,¹² jazz, rock and roll, impressionism, surrealism. This includes those that look plural but function as grammatically singular in English: mathematics, physics, mechanics, dynamics, statics, thermodynamics, aerodynamics, electronics, hydrodynamics, robotics, acoustics, optics, computer graphics, cryptography, ethics, linguistics, etc.; e.g., Mathematics is fun; Cryptography is the science of codes and ciphers; theromodynamics is the science of heat.

• Chemical elements and other physical entities:

aluminum, copper, gold, oxygen, nitrogen, carbon, equipment, furniture, traffic, species, earth, air, fire, and water

^ Note 12: Referring to the musical style as a whole.

Some mass nouns can be pluralized, but the meaning in this case may change somewhat. For example, when I have two grain(s) of sand, I do not have two sands; I have sand. There is more sand in your pile than in mine, not more sands. However, there could be the many sands of Africa — either many distinct stretches of sand, or distinct types of sand of interest to geologists or builders, or simply the allusive The Sands of Mars.

It is rare to pluralize furniture in this way. Nor is information ever pluralized.

There is only one class of atoms called oxygen, but there are several isotopes of oxygen, which might be referred to as different oxygens. In casual speech, oxygen might be used as shorthand for oxygen atoms, but in this case, it is not a mass noun, so it is entirely sensible to refer to multiple oxygens in the same molecule.

One would interpret Bob's wisdoms as various pieces of Bob's wisdom (that is, don't run with scissors, defer to those with greater knowledge), deceits as a series of instances of deceitful behavior (lied on income tax, dated my wife), and the different idlenesses of the worker as plural distinct manifestations of the mass concept of idleness (or as different types of idleness, bone lazy versus no work to do).

Specie versus species make a fascinating case. Both words come from a Latin word meaning kind, but they do not form a singular-plural pair. In Latin, specie is the ablative singular form, while species is the nominative form, which happens to be the same in both singular and plural. In English, species behaves similarly —as a noun with identical singular and plural— while specie is treated as a mass noun, referring to money in the form of coins (the idea is of [payment] in kind).^[22]

[edit] Plurals of compound nouns

The majority of English compound nouns have one basic term, or head, with which they end, and are pluralized in typical fashion:

able seaman	able seamen
head banger	head bangers
yellow-dog contract	yellow-dog contracts

A compound that has one head, with which it begins, usually pluralizes its head:

attorney general	attorneys general
bill of attainder	bills of attainder
court martial	courts martial
director general	directors general
fee simple absolute	fees simple absolute
governor-general	governors-general
passerby	passersby
ship of the line	ships of the line
son-in-law	sons-in-law
minister-president	ministers-president
knight-errant	knights-errant
procurator fiscal (in Scotland)	procurators fiscal

It is common in informal speech to instead pluralize the last word in the manner typical of most English nouns, but in edited prose, the forms given above are preferred.

If a compound can be thought to have two heads, both of them tend to be pluralized when the first head has an irregular plural form:

man-child	men-children
manservant	menservants
woman doctor	women doctors

Two-headed compounds in which the first head has a standard plural form, however, tend to pluralize only the final head:

city-state	city-states
nurse-practitioner	nurse-practitioners
scholar-poet	scholar-poets

In military usage, the term general, as part of an officer's title, is etymologically an adjective, but it has been adopted as a noun and thus a head, so compound titles employing it are pluralized at the end:

brigadier general	brigadier generals
major general	major generals

For compounds of three or more words that have a head (or a term functioning as a head) with an irregular plural form, only that term is pluralized:

man-about-town	men-about-town
man-of-war	men-of-war
woman of the street	women of the street

For many other compounds of three or more words with a head at the front —especially in cases where the compound is ad hoc and/or the head is metaphorical— it is generally regarded as acceptable to pluralize either the first major term or the last (if open when singular, such compounds tend to take hyphens when plural in the latter case):

ham on rye	hams on rye/ham-on-ryes
jack-in-the-box	jacks-in-the-box/jack-in-the-boxes
jack-in-the-pulpit	jacks-in-the-pulpit/jack-in-the-pulpits

With a few extended compounds, both terms may be pluralized—again, with an alternative (which may be more prevalent, e.g., heads of state):

head of state	heads of states/heads of state
son of a bitch	sons of bitches/sons-of-a-bitch

With extended compounds constructed around o', only the last term is pluralized (or left unchanged if it is already plural):

cat-o'-nine-tails	cat-o'-nine-tails
jack-o'-lantern	jack-o'-lanterns
will-o'-the-wisp	will-o'-the-wisps

[edit] Compounds from the French

Many English compounds have been borrowed directly from the French, and these generally follow a somewhat different set of rules. French-loaned compounds with a head at the beginning tend to pluralize both words, according to French practice:

agent provocateur	agents provocateurs
entente cordiale	ententes cordiales
fait accompli	faits accomplis
idée fixe	idées fixes

For compounds adopted directly from the French where the head comes at the end, it is generally regarded as acceptable either to pluralize both words or only the last:

beau geste	beaux gestes/beau gestes
belle époque	belles époques/belle époques
bon mot	bons mots/bon mots
bon vivant	bons vivants/bon vivants
bel13 homme	beaux hommes

^ Note 13: If the adjectives beau beautiful/handsome, nouveau new, or vieux old precede a masculine singular noun beginning with a vowel or a mute h, they are changed to bel, nouvel, and vieil to help ease the pronunciation. The normal plural rule applies to plural nouns.

French-loaned compounds longer than two words tend to follow the rules of the original language, which usually involves pluralizing only the head at the beginning:

aide-de-camp	aides-de-camp
cri du coeur	cris du coeur
coup d'état	coups d'état
tour de force	tours de force

but:

tête-à-tête

tête-à-têtes

A distinctive case is the compound film noir. For this French-loaned artistic term, English-language texts variously use as the plural films noirs, films noir, and, most prevalently, film noirs. The 11th edition of the standard Merriam-Webster's Collegiate Dictionary (2006) lists film noirs as the preferred style. Three primary bases may be identified for this:

1. Unlike other compounds borrowed directly from the French, film noir is used to refer primarily to English-language cultural artifacts; a typically English-style plural is thus unusually appropriate.
2. Again, unlike other foreign-loaned compounds, film noir refers specifically to the products of popular culture; consequently, popular usage holds more orthographical authority than is usual.
3. English has adopted noir as a stand-alone noun in artistic contexts, leading it to serve as the lone head in a variety of compounds (e.g., psycho-noir, sci-fi noir).

See also the headless nouns section below.

[edit] Plurals (and singulars) of headless nouns

In The Language Instinct, linguist Steven Pinker discusses what he calls headless words, typically bahuvrihi compounds, like lowlife and Red Sox, in which life and sox are not heads semantically; that is, a lowlife is not a type of life, nor are Red Sox a group of similarly colored socks. When the common form of such a word is singular, it is treated as if it has a regular plural, even if the final constituent of the word is usually pluralized in a nonregular fashion. Thus, more than one lowlife are lowlifes, not lowlives, according to Pinker. A related process can be observed with the compound maple leaf, pluralized in its common-noun form as maple leaves; when it is adopted as the name of an ice-hockey team, its plural becomes Maple Leafs. Other proposed examples include:

flatfoot	flatfoots
sabertooth	sabertooths
still life	still lifes
tenderfoot	tenderfoots

An exception is Blackfoot, of which the plural can be Blackfeet, though that form of the name is officially rejected by the Blackfoot First Nations of Canada.

Where words have taken on completely new meanings, irregular plurals may become regularized. Antennas is the accepted plural of antenna when it refers to electromagnetic equipment, in contrast to antennae for arthropods' and insects' feelers. The computer mouse is sometimes considered headless and pluralized as mouses, but also often as mice; in contrast to the compound headless words just discussed, there is a considerably stronger metaphorical relationship in this case, with many computer pointing devices resembling rodents with tails.

In other cases, the common form of a headless word is a nonregular plural; when such a word lacks a terminal s, it is treated as defective, thus making the singular version of the word identical: an individual member of the Boston baseball team is a Red Sox, just as all twenty-five are. One Chicago White Sox is a White Sox (questionable).

[edit] Related collective nouns

Sports team names like those discussed above —as well as more grammatically ordinary names such as Reds, Knicks, and Canadiens, and straightforward compound names such as Blue Jays — form a particular set of collective nouns. Closely related to the class of essentially plural headless nouns typified by Red Sox are the growing number of orthographically singular sports team names that may be classified as examples of a special type of collective noun — one that (a) has identical terms for both the collective and an individual thereof (as with the essentially plural headless noun) but (b) is not used as a counting noun beyond the singular. Two examples include the name of the NBA team of Miami, Florida — the Miami Heat — and the name of the Colorado NHL team —the Colorado Avalanche. While heat is a mass noun, whereas avalanche is a normal counting noun, in the context of a team name, both words operate as this special type of collective noun. Just as with the Red Sox or the White Sox, any one of the twelve current members of Miami's pro basketball squad is a Heat (questionable). Similarly, any individual member of the Colorado Avalanche is an Avalanche. However, where one may say something like two Red Sox struck out or four White Sox doubled consequitively, the equivalent term is invariably used as an adjective when referring to multiple players of one of the teams named in this increasingly popular way: two Heat players fought or four Avalanche players scored (The followers of the Avalanche have a little more flexibility available to them, with Avs as the team's unofficial, but widely used nickname). Other examples include:

NHL	WNBA
Tampa Bay Lightning	strawberry silver and gold investment