Irregular Plural Nouns: Useful Rules, List & Examples 1

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 Video

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

NOUNS: Useful Grammar Rules, List & Examples

English Nouns

6 Comments

  1. Gregory S Kharmalki, PhD June 10, 2018
  2. Smc June 12, 2018
  3. Galia July 27, 2018
  4. Anonymous September 13, 2018
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