Irregular Plural Nouns: Useful Rules, List & Examples

Irregular Plural Nouns! Learn useful grammar rules to form Irregular Plural Nouns in English. Learn practical list of irregular nouns with examples and ESL worksheets.

Irregular Plural Nouns | No Change in the Plural

Some nouns have identical singular and plural. Many of these are the names of animals.

Irregular Plural Nouns List:

  • Aircraft – aircraft
  • Barracks – barracks
  • Deer – deer
  • Gallows – gallows
  • Moose – moose
  • Salmon – salmon
  • Hovercraft – hovercraft
  • Spacecraft – spacecraft
  • Series – series
  • Species – species
  • Means – means
  • Offspring – offspring
  • Deer – deer
  • Fish – fish
  • Sheep – sheep
  • Offspring – offspring
  • Trout – trout
  • Swine – swine

Irregular Plural Nouns | Changing the Spelling of the Singular Noun

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

Irregular Plural Nouns List:

  • Person – people
  • Ox – oxen
  • Man – men
  • Woman – women
  • Caveman – cavemen
  • Policeman – policemen
  • Child – children
  • Tooth – teeth
  • Foot – feet
  • Goose – geese
  • Mouse – mice
  • Louse – lice
  • Penny – pence

Note: There are many compounds of man and woman that form their plurals in the same way: postmen, policewomen, etc.

Irregular Nouns – Image 1

Irregular Plural Nouns

Irregular Plural Nouns from Latin and Greek

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

  • Alumna – alumnae
  • Formula – formulae/formulas

Final ex or ix becomes -ices

  • Index – indices /indexes
  • Matrix – matrices
  • Vertex – vertices
  • Appendix – appendices

Final is becomes es

  • Axis – axes
  • Genesis – geneses
  • Nemesis – nemeses
  • Crisis – crises
  • Testis – testes

Final um becomes -a, or just adds -s

Irregular Plural Nouns List:

  • Addendum – addenda
  • Corrigendum – corrigenda
  • Datum – data
  • Forum – fora/forums
  • Medium – media/ mediums
  • Memorandum – memoranda/memorandums
  • Millennium – millennia
  • Ovum – ova
  • Spectrum – spectra

Final us becomes -i or -era or -ora or just adds -es

Irregular Plural Nouns List:

  • Alumnus – alumni
  • Corpus – corpora
  • Census – censuses
  • Focus – foci
  • Genus – genera
  • Prospectus – prospectuses
  • Radius – radii
  • Campus – campuses
  • Succubus – succubi
  • Stylus – styli
  • Syllabus – syllabi/syllabuses
  • Viscus – viscera
  • Virus – viruses/virii
  • Cactus – cactuses/cacti
  • Fungus – fungi
  • Hippopotamus – hippopotamuses/hippopotami
  • Octopus – octopuses
  • Terminus – termini/terminuses
  • Uterus – uteri/uteruses

Final us remains unchanged in the plural

  • Meatus – meatus/meatuses
  • Status – status/statuses

Final on becomes -a

  • Automaton – automata
  • Criterion – criteria
  • Phenomenon – phenomena
  • Polyhedron – polyhedra

Final as in one case changes to -antes

  • Atlas – Atlantes (statues of the Titan); but Atlas – atlases (map collections)

Final ma in nouns of Greek origin can become -mata

Final ma in nouns of Greek origin can become -mata, 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

Irregular Plural Nouns from Other Languages

Some nouns of French origin add an -x:

  • Beau – beaux/beaus
  • Bureau – bureaux/bureaus
  • Tableau – tableaux/tableaus

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

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

  • Benshi – benshi
  • Otaku – otaku
  • Samurai – samurai

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

  • Canoe – canoes
  • Igloo – igloos
  • Kangaroo – kangaroos
  • Kayak – kayaks
  • Kindergarten – kindergartens
  • Pizza – pizzas
  • Sauna – saunas
  • Ninja – ninjas

Irregular Nouns – Image 2

Irregular Plural Nouns

Irregular Plural Nouns Videos

Learn more useful rules to form regular plural nouns in English.

NOUNS: Useful Grammar Rules, List & Examples

English Nouns

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Gregory S Kharmalki, PhD
Gregory S Kharmalki, PhD
2 years ago

Thank you. Some if the words are so simple that we tend to get confused, especially, the Latin words. My students are amazed.
Thank you once again.

Smc
Smc
2 years ago

Thank u

Galia
Galia
2 years ago

Thank you very much you are the best

Anonymous
Anonymous
2 years ago

thank u so much!

Anonymous
Anonymous
1 year ago

Thank you so much!!!

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