
A noun is a type of word which refers to a person, place, or thing. Nouns can be conjugated in either singular or plural form. A singular noun refers to just one person, place, or thing (for example, a bat or a ship). A plural noun refers to multiple people, places, or things (for example, bats or ships).
The majority of English count nouns are regular and predictable in the spelling of the plural form1. However, other nouns have irregular plural spellings. Both of these kinds of nouns will be covered here.
Rule #1: Add -s
Most nouns can be pluralized simply by adding an -s at the end of the word. For example:
- edge/edges
- girl/girls
- song/songs
- bag/bags
- cat/cats
- boy/boys
- day/days
Rule #2: Add -es to nouns ending in s, z, ch, sh, and x
Nouns which end in the letters s, z, ch, sh, and x-es at the end. For example:
- glass/glasses
- horse/horses
- buzz/buzzes
- dish/dishes
- box/boxes
- bush/bushes
- witch/witches
- switch/switches
Rule #3: Nouns ending in o
For words ending in the letter o, sometimes they are pluralized by adding s, while other words must be pluralized by adding es. These words must be memorized, because there is no simple rule to explain the differences.2
Examples (es):
- echo/echoes
- embargo/embargoes
- hero/heroes
- potato/potatoes
- veto/vetoes
- tomato/tomatoes
- torpedo/torpedoes
- hero/heroes
- veto/vetoes
Examples (s):
Most nouns ending in o preceded by a vowel are pluralized by simply adding s3. Some other o nouns do this, too:
- auto/autos
- folio/folios
- cameo/cameos
- portfolio/portfolios
- kilo/kilos
- photo/photos
- zoo/zoos
- memo/memos
- solo/solos
- soprano/sopranos
- studio/studios
- pimento/pimentos
- tattoo/tattoos
- video/videos
- piano/pianos
- pro/pros
- kangaroo/kangaroos
Rule #4: Nouns Ending in a consonant Y
For nouns ending in the letter y, replace the ending y with ies. For example:
- baby/babies
- story/stories
- poppy/poppies
- baby/babies
- daisy/daisies
- spy/spies
- lady/ladies
Note that for words ending in y preceeded by a vowel (a complex vowel sound), an s is simply added, as usual. For example:
- day/days
- toy/toys
- essay/essays
- turkey/turkeys
- chimney/chimneys
- play/plays
- joy/joys
- valley/valleys
- alley/alleys
- volley/volleys
(Irregular) Some nouns Ending in -F or -FE
For some nouns ending in f or fe, replace the ending f or fe with ves:
- calf/calves
- elf/elves
- half/halves
- hoof/hooves
- leaf/leaves
- life/lives
- loaf/loaves
- scarf/scarves
- self/selves
- sheaf/sheaves
- wolf/wolves
- shelf/shelves
- thief/thieves
- knife/knives
- wife/wives
(Irregular) Some nouns change the vowel sound in becoming plural:
- fireman/firemen
- foot/feet
- goose/geese
- louse/lice
- man/men
- mouse/mice
- tooth/teeth
- woman/women
(Irregular) Some Old English plurals are still in use:
Nouns adopted from other languages4
Singular ends in -IS
For nouns in which the singular form ends in is, the plural form will end in es. For example:
- hypothesis/hypotheses
- diagnosis/diagnoses
- ellipsis/ellipses
- analysis/analyses
- basis/bases
- crisis/crises
- thesis/theses
- oasis/oases
- synthesis/syntheses
- synopsis/synopses
- emphasis/emphases
- neurosis/neuroses
- paralysis/paralyses
- parenthesis/parentheses
Singular ends in -UM
Plural ends in a:
- bacterium/bacteria
- datum/data
- curriculum/curricula
- medium/media
- memorandum/memoranda
- ovum/ova
- symposium/symposia
- erratum/errata
- addendum/addenda
- stratum/strata
Singular ends in -ON
Plural ends in -a
- criterion/criteria
- phenomenon/phenomena
- automaton/automata
Singular ends in -A
Plural ends in -ae
- alga/algae
- amoeba/amoebae
- larva/larvae
- formula/formulae
- antenna/antannae
- nebula/nebulae
- vertebra/vertebrae
- vita/vitae
Singular ends in -ex or -ix
Plural ends in -ices:
- appendix/appendices
- index/indeces
- matrix/matrices
- vertex/vertices
- vortex/vortices
- apex/apices
- cervix/cervices
- axis/axes
Singular ends in -us
Plural ends in -i:
- alumnus/alumni
- bacillus/bacilli
- cactus/cacti
- focus/foci
- stimulus/stimuli
- focus/foci
- octopus/octopi
- radius/radii
- stimulus/stimuli
- terminus/termini
Singular ends in -us:
Plural ends in -a:
- corpus/corpora
- genus/genera
Singular ends in -eau
Plural ends in -eaux:
- bureau/bureaux
- beau/beaux
- portmanteau/portmanteaux
- tableau/tableaux
Other irregular plurals, retained from different languages:
Italian
- libretto/libretti
- tempo/tempi
- virtuoso/virtuosi
Hebrew
- cherub/cherubim
- seraph/seraphim
Greek
Other Irregular Plurals
- man/men
- woman/women
- fungus/fungi
- species/species
- medium/media
- person/people
- foot/feet
- tooth/teeth
- goose/geese
- mouse/mice
- louse/lice
- child/children
- penny/pence
- ox/oxen
Posessive Plurals
For plural nouns ending in the letter s, add only the apostrophe. For example:
- The Johnsons' farm
- Singers' voices
- The thieves' guild
For plural nouns not ending in the letter s, add an apostrophe and s. For example:
- Women's soccer
- Children's books
Words Which are Always Plural or Always Singular
Some nouns are always plural or always singular. Some other nouns have the same form for singular and plural.5
Some nouns are always plural (things that come in pairs):
- pants
- clothes
- binoculars
- jeans
- forceps
- trousers
- tongs
- shorts
- tweezers
- people
- pajamas
- police
- shorts
- glasses
- scissors
- mathematics
Aggregate Nouns
Some nouns end in -s but have no singular (these are called aggregate nouns). These are traditionally plural, but are also used for singular forms:
- accomodations
- bread
- amends
- tea
- archives
- cheese
- bowels
- jam
- communications
- soup
- congratulations
- soap
- contents
- snow
- stairs
- cotton
- wood
- thanks
- water
- goods
- information
- advice
- knowledge
- furniture
- news
- means
- series
- species
- barracks
- crossroads
- gallows
- headquarters
Nouns with the same form
Some nouns have the same form for singular and plural, such as fish and animals. (Note that not all fish have the irregular plural form, though--e.g., one shark becomes two sharks)
- salmon
- trout
- deer
- sheep
- swine
- offspring
1 Griselda, 2007
2 Crump, 1997
3 Schmitt, 2004
4 Byrd, 2007
5 Janssens, 2004