Plural Nouns

The plural of a noun is usually formed by adding an 's' at the end of the word. For example: the plural of cat is cats; the plural of flower is flowers, and the plural of computer is computers.

If the word ends in s, x, z, ch, or sh, the plural is usually formed by adding 'es.' This is because when you add an 's' to the end of these words, you have to add an extra syllable to the the word in order to prounounce it. For example: the plural of boss is bosses, the plural of box is boxes, the plural of buzz is buzzes, the plural of lunch is lunches, and the plural of brush is brushes.

Not all plurals end in 's' or 'es'. Irregular nouns are those that do not use the regular plural ending. The following are some irregular plurals.

Type of Noun	Rule for Forming the Plural	Examples	Exceptions
Word ends in s, x, ch, or sh	Add 'es' to the end	arch/arches, atlas/atlases, ax/axes, bash/bashes, bench/benches, bias/biases, botch/botches, box/boxes, brush/brushes, bunch/bunches, bus/buses, bush/bushes, canvas/canvases, catch/catches, church/churches, class/classes, compass/compasses, crash/crashes, cross/crosses, dais/daises, dish/dishes, dress/dresses, equinox/equinoxes, etch/etches, fetch/fetches, fix/fixes, fox/foxes, gas/gases, grass/grasses, itch/itches, kiss/kisses, larch/larches, lash/lashes, latch/latches, mantis/mantises, march/marches, marsh/marshes, mash/mashes, mass/masses, match/matches, moss/mosses, mix/mixes, pass/passes, patch/patches, pox/poxes, radish/radishes, sash/sashes, sketch/sketches, starch/starches, stitch/stitches, tax/taxes, touch/touches, trash/trashes, twitch/twitches, vehicle/vehicles, wish/wishes, witch/witches, wrench/wrenches	axis/axes, ox/oxen
Word ends in z	Add 'zes' to the end	buzz/buzzes, fizz/fizzes, klutz/klutzes, quiz/quizzes, topaz/topazes, waltz/waltzes
Ending in 'y' preceded by a vowel	Add an 's'	alley/alleys, attorney/attorneys, essay/essays, boy/boys, delay/delays, guy/guys, jay/jays, key/keys, osprey/ospreys, play/plays, ray/rays, stray/strays, toy/toys, tray/trays, turkey/turkeys, valley/valleys, way/ways
Ending in 'y' preceded by a consonant	Change the final 'y' to 'ies'	ally/allies, army/armies, baby/babies, beauty/beauties, berry/berries, cherry/cherries, city/cities, colony/colonies, country/countries, dictionary/dictionaries, duty/duties, enemy/enemies, fairy/fairies, family/families, ferry/ferries, fly/flies, gallery/galleries, history/histories, injury/injuries, jelly/jellies, kitty/kitties, lady/ladies, lily/lilies, navy/navies, history/histories, party/parties, pony/ponies, reply/replies, secretary/secretaries, sky/skies, spy/spies, story/stories, study/studies, symphony/symphonies, theory/theories, trophy/trophies, try/tries, university/universities, variety/varieties, victory/victories
Ends with 'f' or 'fe' (but not 'ff' or 'ffe')	Change the 'f' or 'fe' to 'ves'	calf/calves, elf/elves, half/halves, hoof/hooves, knife/knives, leaf/leaves, life/lives, loaf/loaves, knife/knives, loaf/loaves, scarf/scarves, self/selves, shelf/shelves, wife/wives, wolf/wolves	belief/beliefs, chef/chefs, chief/chiefs, dwarf/dwarfs, grief/griefs, gulf/gulfs, handkerchief/handkerchiefs, kerchief/kerchiefs, mischief/mischiefs, muff/muffs, oaf/oafs, proof/proofs, roof/roofs, safe/safes, turf/turfs
Ends with 'o'	Add 'es'	buffalo/buffaloes, cargo/cargoes, echo/echoes, embargo/embargoes, grotto/grottoes, hero/heroes, mosquito/mosquitoes, motto/mottoes, potato/potatoes, tomato/tomatoes, torpedo/torpedoes, veto/vetoes, volcano/volcanoes, zero/zeroes	albino/albinos, armadillo/armadillos, auto/autos, cameo/cameos, cello/cellos, combo/combos, duo/duos, ego/egos, folio/folios, halo/halos, inferno/infernos, lasso/lassos, memento/mementos, memo/memos, piano/pianos, photo/photos, portfolio/portfolios, pro/pros, silo/silos, solo/solos, stereo/stereos, studio/studios, taco/tacos, tattoo/tattoos, tuxedo/tuxedos, typo/typos, veto/vetoes, video/videos, yo/yos, zoo/zoos
Irregular	Variable	child/children, die/dice, foot/feet, goose/geese, louse/lice, man/men, mouse/mice, ox/oxen, person/people, that/those, this/these, tooth/teeth, woman/women
Ends with 'is' (from a Greek root)	Change final 'is' to 'es'	analysis/analyses, axis/axes, basis/bases, crisis/crises, ellipsis/ellipses, hypotheses/hypothesis, neurosis/neuroses, oasis/oases, paralysis/paralyses, parenthesis/parentheses, synopsis/synopses, synthesis/syntheses, thesis/theses
Ends with 'us' (if the word is from the Latin)	Change final 'us' to 'i'	alumnus/alumni, bacillus/bacilli, cactus/cacti, focus/foci, fungus/fungi, locus/loci, nucleus/nuclei, radius/radii, stimulus/stimuli, syllabus/syllabi, terminus/termini, torus/tori	abacus/abacuses, crocus/crocuses, genus/genera, octopus/octopuses (not octopi, since octopus is from the Greek language), rhombus/rhombuses, walrus/walruses
Ends with 'um'	Change final 'um' to 'a'	bacterium/bacteria, curriculum/curricula, datum/data, erratum/errata, gymnasium/gymnasia, medium/media, memorandum/memoranda, ovum/ova, stratum/strata	album/albums, stadium/stadiums
Ends with 'a' but not 'ia' (from a Latin root)	Change final 'a' to 'ae'	alga/algae, alumna/alumnae, antenna/antennae, larva/larvae, nebula/nebulae, pupa/pupae (or pupas), vertebra/vertebrae, vita/vitae	agenda/agendas, alfalfa/alfalfas, aurora/auroras, banana/bananas, barracuda/barracudas, cornea/corneas, nova/novas, phobia/phobias
Ends with 'on' (from a Greek root -- not 'tion')	Change final 'on' to 'a'	automaton/automata, criterion/criteria, phenomenon/phenomena, polyhedron/polyhedra	balloon/balloons, carton/cartons and many, many others
Ends with 'ex'	Change final 'ex' to 'ices'	vertex/vertices, vortex/vortices	annex/annexes, complex/complexes, duplex/duplexes, hex/hexes, index/indexes or indices
Unchanging	Singular and plural are the same	advice, aircraft, bison, corn, deer, equipment , evidence, fish (sometimes), gold, information, jewelry, kin, legislation, luck, luggage, moose, music, offspring, sheep, silver, swine, trousers, trout, wheat
Only the plural exists	Unchanging	barracks, bellows, cattle, congratulations, deer, dregs, eyeglasses, gallows, headquarters, mathematics, means, measles, mumps, news, oats, pants, pliers, pajamas, scissors, series, shears, shorts, species, tongs, tweezers, vespers
Compound nouns	The plural ending is usually added to the main noun	attorney general/attorneys general, bill of fare/bills of fare, chief of staff/chiefs of staff, court-martial/courts-martial, daughter-in-law/daughters-in-law, father-in-law/fathers-in-law, full moon/full moons, he-man/he-men, journeyman/journeymen, lady-in-waiting/ladies-in-waiting, lieutenant colonel/lieutenant colonels, maid-of-honor, maids-of-honor, master-at-arms/masters-at-arms, middle class/middle classes, mother-in-law/mothers-in-law, post office/post offices, secretary of state/secretaries of state, sergeant major/sergeants major, son-in-law/sons-in-law, passer-by/passers-by, she-wolf/she-wolves, stepsister/stepsisters, ten-year-old/ten-year-olds

Note: Collective nouns are words for a group of items or beings. For example, a group of cows is called a herd, a group of baseball players is called a team, and a group of ants is called a colony. For some collective nouns for groups of animals, click here.