An English plural—that is, the plural form of a singular noun—is most commonly formed by adding an s to the singular form (though it is generally pronounced as a z except after an unvoiced consonant):
boy boys girl girls cat cats table tables
There are many other ways of forming "irregular" plurals. While they may seem quirky, they usually stem from older forms of English or from a foreign borrowings.
Where a noun ends in a sibilant sound—such as s, sh, x, soft ch—the plural is formed by adding es (also pronounced as z with a neutral vowel sound):
glass glasses dish dishes witch witches
Nouns ending in o preceded by a consonant also form their plurals by adding es:
hero heroes potato potatoes volcano volcanoes
Nouns of Italian or Spanish origin are exceptions to this rule:
canto cantos grotto grottos piano pianos portico porticos quarto quartos solo solos
Most nouns ending in f or fe form their plurals by changing the f into a v and adding es:
calf calves half halves
Some just add an s:
proof proofs muff muffs
Some can do either:
dwarf dwarf / dwarves hoof hoofs / hooves roof roofs / rooves staff staffs / staves turf turfs / turves
- Dwarf is an interesting case: 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 came along and popularised dwarves. Multiple dwarf stars, or non-mythological short human beings, however, are dwarfs.
- Staff: in the sense of "a body of employees" the plural is always staffs; otherwise both staffs and staves are acceptable, except in compounds; such as flagstaffs.
Nouns ending in y preceded by a consonant change their ending to ies:
cherry cherries lady ladies
The plural of a few Germanic nouns can also be formed from the singular by adding n or en:
ox oxen eye eyen (Rare, found in some regional dialects) shoe shoon (Also rare)
The plural is sometimes formed by simply changing the vowel sound of the singular, in a process called umlaut (these are sometimes called mutated plurals):
foot feet goose geese louse lice man men mouse mice tooth teeth woman women
Some nouns have singular and plural alike:
sheep deer cod series trout
Some nouns have no singular form:
annals billiards cattle clothes measles nuptials thanks tidings victuals / vittles
Neither do some names of things having two parts:
scissors trousers tweezers pants
Note, however, that the fashion industry frequently calls a single pair of pants a pant; this is a back-formation.
Some words in which the modifier follows the noun form the plural inside the word or phrase, particularly legal terms from French:
attorney general attorneys general son-in-law sons-in-law court martial courts martial armful armsful / armfuls (the latter is preferred today) governor-general governors-general
Some nouns have no plural form:
- abstract nouns
goodness idleness wisdom
Note, however, that if Wisdom is used as a title ("Your Wisdom") it is then given a regular plural—Their Wisdoms.
- non-countable nouns, such as chemical elements and substances:
antimony gold oxygen furniture specie distress
- arts and sciences (even those ending in ics are treated as singular)
chemistry geometry surgery biometrics mechanics optics blues (music)
- Specie and species make a fascinating case. Both words come from a Latin word meaning "kind", but they do not form a singular-plural pair; they are separate non-countable nouns. Coins, such as nickels, euros, and cents are specie, but there is no plural. The idea is "payment in kind". And species, the "kinds of living things", is the same in singular and plural.
- Some names of elements, such as nickel, have plurals in non-chemical uses, as "five nickels to the quarter".
- Some non-countable substance nouns like "tea" or "wood" have plurals that mean "varieties of..." tea, wood, etc.
Some nouns have two plurals, one used to refer to a number of things considered individually, the other to refer to a number of things collectively. In some cases, one of the two is nowadays archaic or dialectal.
brother brothers brethren cannon cannons cannon child childer children cow cows kine die dies dice fish fishes fish penny pennies pence sow sows swine pig pigs swine iris iris irises
- Childer has all but disappeared, but can still be seen in Childermas (Innocents' Day)
- Kine is still used in rural English dialects
- Dies is used as the plural for die in the sense of a mould; dice as the plural (and increasingly as the singular) in the sense of a small random number generator
- Fish: the plural for one species of fish, or caught fish, is fish, but for live fish of many species, or in poetic usage, fishes is used.
- For multiple plants, say iris, but for multiple blossoms say irises.
- If you have several (British) one-penny pieces you have several pennies; pence is used for an amount of money (which can be made up of a number of coins of different denominations: one penny and one five-penny piece are together worth six pence); penny and pennies are also use to refer to one or more U.S. one-cent pieces
- The plurals of child and brother as children and brethren are considered self-conscious coinages, just as in VAX and VAXen, although considerably older.
A final odd case is person. The word people is usually treated as the suppletive plural of person (one person, many people). However, in legal and other formal contexts, the plural of person is persons; furthermore, people can also be a singular noun with its own plural (for example, "We are many persons, from many peoples").
Symbols and abbreviations whose plural would be ambiguous if only an s were added are pluralized by adding 's.
mind your p's and q's
Regular words are never pluralized in this way, nor are abbreviations made from initials without periods, as in PCs and ICBMs.
More on plurals of English words of foreign origin
Because English includes words from so many ancestral languages, as well as many loanwords from Classical Greek and Latin and other modern languages, there are many other forms of plurals. Such nouns often retain their original plurals, at least for some time after they are introduced. In some cases both forms are still vying for attention: for example, for a librarian, the plural of appendix is appendices (following the original language); for physicians, however, the plural of appendix is appendixes. Likewise, an electrician works with antennas and an entomologist deals with antennae. The "correct" form is the one that sounds the better in context.
Correctly formed Latin plurals are the most acceptable, and indeed are often required, in academic and scientific contexts.
- Final a becomes ae (strictly æ)—or just adds s:
formula formulae / formulas alumna alumnae
- Final ex becomes ices— or just adds es:
vertex vertices index indices / indexes
- Final is becomes es:
axis axes testis testes
- Final on becomes a:
phenomenon phenomena (more below) criterion criteria
- Final um becomes a – or just adds s
addendum addenda memorandum memoranda / memorandums
- Final us becomes i (second declension) or era (third declension)—or just adds es (especially in fourth declension, where it would otherwise be the same as the singular):
radius radii alumnus alumni viscus viscera virus viruses
Note: in Latin, virus has no plural form. Viri and virii are both incorrect.
- Final ma in nouns of Greek origin add ta:
stigma stigmata stoma stomata
Though some take s more commonly:
schema schemata or schemas dogma dogmata or dogmas
- Final us in nouns of Greek origin add es
cactus cactuses hippopotamus hippopotamuses octopus octopuses platypus platypuses / platypus rhinoceros rhinoceroses / rhinoceros
Of course, the Latinate i plural is frequently heard for these words, but it is considered an error of pedantic hypercorrectness that is not generally accepted in formal use despite having made its way into some dictionaries. (The Greek plural for words ending in -pus meaning "foot", is podes, but that plural is not used in English.)
- Some nouns of French origin add x
beau beaux chateau chateaux
- Nouns of Hebrew origin add im or ot (generally m/f)—or just s
note that ot is pronounced os in Ashkenazi
cherub cherubim / cherubs seraph seraphim / seraphs matzoh matzot / matzos
- Nouns of Japanese origin have no plural and do not change:
kimono kimono samurai samurai otaku otaku
Note: kimonos, following the French model, is now generally accepted in English.
Nouns from languages that have donated few words to English, and that are spoken by relatively few English-speakers, generally form plurals as if they were native English words:
canoe canoes kayak kayaks igloo igloos cwm cwms (Welsh valley)
Some words of foreign origin are much better known in the plural, while the singular is hardly ever heard except from the fully precise, and with the plural usually taking a singular verb:
candelabrum candelabra datum data agendum agenda graffito graffiti insigne insignia viscus viscera alga algae opus opera phalanx phalanges
Insignia is sometimes counted as a singular form with insignias as its plural, but this usage comes across as illiterate to many people. The singular form insigne is now very rare and sounds absurdly pedantic, so the safest bet is to use insignia only as a plural and to substitute a close synonym (such as symbol or emblem) in place of the singular.
There is an even worse problem with the word data. Although its use as a mass noun is gaining acceptance, to many people it sounds wrong whether used as a singular or as a plural! "The data is" seems jarringly incorrect but "the data are" seems equally jarringly pedantic. The safe way is to use the word only if it would be correct whether singular or plural (for example, "we checked the data"), and to substitute a synonym in other contexts (for example, "the figures are" or "the information is").
A related phenomenon is the confusion of a foreign plural for its singular form:
phenomenon phenomena criterion criteria symposium symposia
Mouses is sometimes seen for computer pointing devices, although mice is probably more common.
Plural to singular by back formation
Some words have started out with unusually formed singulars and plurals, but more "normal" singular-plural pairs have resulted. For an example from the vegetable world, pease was the singular and peasen the plural, but over the centuries, first pease became the plural and pea the singular, and finally the plural was altered to peas. Similarly, termites and primates were the three-syllable plurals of termes and primas, respectively, but these singulars were lost, the plurals given two syllables, and now we have termite and termites and primate and primates. Syringe is a back formation from syringes, itself the plural of syrinx, a musical instrument. Finally, phases was once the plural of phasis, but the singular is now phase.
Kudos is a singular Greek word meaning praise, but the same process may be happening to it. At present, kudo is an error, however.
Names of peoples
There are several different rules for this.
In discussing peoples whose demonym takes -man or -woman, there are two options: pluralize to -men or -women if referring to individuals, and use the root alone if referring to the whole nation.
Englishman Englishmen the English
Frenchwoman Frenchwomen the French
Dutchman or Dutch people the Dutch
Dutchwoman
This also applies to the Irish and the Welsh. One can say "a Scots(wo)man" or "a Scot", "Scots(wo)men", "Scottish people", or "Scots," and "the Scottish" or "the Scots". (Scotch is a drink.)
Several peoples have names that are simple nouns and can be pluralized:
Dane Danes the Danes (or) the Danish
Finn Finns the Finns (or) the Finnish
Swede Swedes the Swedes (or) the Swedish
Spaniard Spaniards the Spaniards (or) the Spanish
(much more common)
Names of peoples that end in -ese take no plural:
Chinese Chinese the Chinese
(or Chinese people)
Neither does Swiss or Quebecois.
Most names for American Aboriginal groups are not pluralized:
Blackfoot Blackfoot Ojibwa Ojibwa Iroquois Iroquois Blood Blood Sne Nay Muxw Sne Nay Muxw Mi'kmaq Mi'kmaq
Some exceptions include Crees, Mohawks, Hurons, Algonquins, Chippewas, Oneidas, Aztecs. Note also:
Inuk Inuit
Most other peoples of the world are pluralized using the normal English rules.