Let’s learn 50 irregular plural nouns – these are nouns that don’t follow the normal rules for forming plurals! Even a lot of native English speakers aren’t sure about how to make the plural forms of these words. When you learn them, you can avoid mistakes and then be confident that your English is correct.
Let’s quickly review how we form regular plural nouns, and then we’ll get to the irregular ones and more complicated cases.
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Regular Plural Nouns:
Add -S
- wall – walls
- ski – skis
- cat – cats
Nouns Ending In -Ch, -Sh, -X, -S Sounds:
Add -ES
- switch – switches
- brush – brushes
- box – boxes
- address – addresses
Exceptions: stomach/stomachs, matrix / matrices
Nouns Ending In consonant-Y:
End With -IES
- baby – babies
- army – armies
- puppy – puppies
If the noun ends in vowel-y: just add -S
- day – days
- key – keys
- toy – toys
Nouns Ending In -O:
-S Or -ES (Depends On The Word!)
Words that end in a vowel + o: Just add -s
- zoo – zoos
- radio – radios
- video – videos
- tattoo – tattoos
Musical words: Just add -s
- solo – solos
- piano – pianos
- cello – cellos
Words from Italian/Spanish: Just add -s
- taco – tacos
- avocado – avocados
- tornado – tornados
- casino – casinos
Shortened words: Just add -s
- photo – photos
- kilo – kilos
- auto – autos
- pro – pros
Always –ES:
- potato/tomato – potatoes/tomatoes
- hero – heroes
- torpedo – torpedoes
- echo – echoes
Some can be both!
- ghetto – ghettos / ghettoes
- mango – mangos / mangoes
- mosquito – mosquitos / mosquitoes
- volcano – volcanos / volcanoes
Nouns Ending In -F Sound: Change To -VES
- knife – knives
- wife – wives
- half – halves
- life – lives
- self – selves
- wolf – wolves
- leaf – leaves
Exceptions: chef/chefs and roof/roofs
VERY Irregular Nouns
- man – men
- woman – women
- child – children
- person – people
- tooth – teeth
- foot – feet
- die – dice
- vertebra – vertebrae
- antenna – antennas (electrical) and antennae (insects)
- mouse – mice
- goose – geese
- ox – oxen
Nouns with the same singular and plural form
- one sheep, two sheep
- one deer, two deer
- one fish, two fish
- one series, two series
- one species, two species
Latin/Greek Nouns: US –> I
- alumnus/alumna – alumni
- cactus – cacti
- focus – foci
Some people do say “focuses.” Alternatively, you could say “points of focus” or “focal points” for the plural of “focus” - fungus – fungi
- nucleus – nuclei
- stimulus – stimuli
- syllabus – syllabi
Latin/Greek Nouns: IS –> ES
- analysis – analyses
- axis – axes
- basis – bases
- crisis – crises
- diagnosis – diagnoses
- hypothesis – hypotheses
- oasis – oases
Latin/Greek Nouns: UM/ON –> A
- bacterium – bacteria
- criterion – criteria
- curriculum – curricula
- datum – data
- millennium – millennia
- phenomenon – phenomena
Learn more: 10 types of nouns
Do you think you can remember all those irregular plural nouns? Try using as many as you can in sentences!
And I’d like to invite you to join me inside my Advanced English Grammar Course. If you’re really looking to take your English to the next level in just about 15 minutes a day, this course will help you get there.
