Contents
Irregular plural nouns can be tricky because they don’t follow the standard rule of adding an “s” or “es” to the end of the singular form. These nouns have unique spellings and can be challenging to master.
In this reference, you will learn what irregular plural nouns are and how to form them. You’ll see examples, common patterns, and tips for identifying and using these nouns correctly. Let’s dive into the world of irregular plural nouns together!
What Are Irregular Plural Nouns?
Irregular plural nouns do not follow the standard rule of adding -s or -es to form their plural version. These nouns are common in English and often require memorization.
Examples of irregular nouns in singular and plural format:
| Singular | Plural |
|---|---|
| Man | Men |
| Foot | Feet |
| Mouse | Mice |
| Child | Children |
| Woman | Women |
| Goose | Geese |
| Person | People |
To use irregular plural nouns correctly, you will need to study and memorize them. Searching for the correct plural forms in the dictionary can also help. Without learning these forms, you might make mistakes when using irregular nouns.
Irregular Plural Nouns | Rules
No Change in the Plural
Some nouns have the same singular and plural forms. Many times, these are names of animals.
- Aircraft – aircraft
- Barracks – barracks
- Deer – deer
- Gallows – gallows
- Moose – moose
- Salmon – salmon
- Hovercraft – hovercraft
- Spacecraft – spacecraft
- Series – series
- Species – species
- Means – means
- Offspring – offspring
- Fish – fish
- Sheep – sheep
- Trout – trout
- Swine – swine
Changing the Spelling of the Singular Noun
The plural form can be made by altering the vowel sound of the singular noun. These are sometimes called mutated plurals.
- 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: Compounds with man and woman follow the same pattern: postmen, policewomen, and others.
Irregular Plural Nouns from Latin and Greek
Final a becomes -ae (also -æ), or just adds -s
- Alumna – alumnae
- Formula – formulae/formulas
- Antenna – antennae/antennas
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
- 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, -era, -ora or just adds -es
- 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 stays the same
- Meatus – meatus/meatuses
- Status – status/statuses
Final on becomes -a
- Automaton – automata
- Criterion – criteria
- Phenomenon – phenomena
- Polyhedron – polyhedra
Final as changes to -antes
- Atlas – Atlantes
Final ma becomes -mata or -s
- Stigma – stigmata/stigmas
- Stoma – stomata/stomas
- Schema – schemata/schemas
- Dogma – dogmata/dogmas
- Lemma – lemmata/lemmas
- Anathema – anathemata/anathemas
Irregular Plural Nouns from Other Languages
Nouns of French origin
Some nouns of French origin add an -x:
- Beau – beaux/beaus
- Bureau – bureaux/bureaus
- Tableau – tableaux/tableaus
Nouns of Slavic origin
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
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
Nouns of Japanese origin
Many nouns of Japanese origin have no plural form and do not change:
- Benshi – benshi
- Otaku – otaku
- Samurai – samurai
Other Languages
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
Frequently Misused Irregular Plural Nouns
Man / Men and Woman / Women: One common mistake is using mans or womans as plural forms. The correct plurals are men and women.
Child / Children: The plural of child is not childs but children.
Mouse / Mice and Goose / Geese: Remember that the plural of mouse is mice, and the plural of goose is geese.
Tooth / Teeth and Foot / Feet: These nouns have plurals that are quite different from their singular forms. The correct plurals are teeth and feet, not tooths and foots.
Person / People: The irregular plural form is people. Note that persons is used in legal contexts or specific situations involving a small number of individuals.
Here is a list of some other irregular plural nouns frequently misused:
| Singular | Correct Plural | Incorrect Plural |
|---|---|---|
| Cactus | Cacti | Cactuses |
| Octopus | Octopuses | Octopi |
| Sheep | Sheep | Sheeps |
| Ox | Oxen | Oxes |
Avoiding these common mistakes will help improve your writing and speaking accuracy.
Irregular Plural Nouns Video
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