Grammar-Monster.com(#gm)

Plural of Platypus

What Is the Plural of Platypus?

homesitemapA-Z plurals platypus

The Quick Answer

The plural of "platypus" is "platypuses."
The plural of "platypus" is "platypuses."
  • Both male and female platypuses are born with ankle spurs, but only the male's spurs produce venom. correct tick
  • In captivity, platypuses have survived up to 17 years of age. correct tick
The noun "platypus" has a Greek root. The Greek plural for "platypus" is "platypodes," but this plural is not used in English. The plural "platypi" is sometimes mistakenly used by people who believe that "platypus" has a Latin derivation, meaning its plural would be "platypi" (in the same way that fungus, cactus, and hippopotamus become fungi, cacti, and hippopotami).

The noun "platypus" adheres to the standard rules for forming the plurals of nouns in English (shown in the table below).

Are You Good at Plurals?

Here's a quick test.
Getting ready...

The Standard Rules for Forming the Plurals

The table below shows the standard rules for forming the plurals of nouns in English.
Type Example of Type Forming the Plural Plural
Most Nouns lamp
scythe
add s lamps
scythes
Noun Ending s, sh, ch, x or z platypus
dress
add es platypuses
dresses
Nouns ending [consonant] o hero
zero
tomato
add either s or es
(There are no rules for this - you have to know.)
heroes
zeros
tomatoes
Nouns ending [vowel] o patio
ratio
add s patios
ratios
Nouns ending [consonant] y story
penny
change the y to an i and add es stories
pennies
Nouns ending [vowel] y donkey
chimney
add s donkeys
chimneys
Nouns ending f or fe dwarf
hoof
ves and/or s
(There are no rules - you have to know.)
dwarfs
hooves or hoofs
Exceptions man
louse
some nouns undergo a vowel or letters change men
lice
More exceptions salmon
sheep
some nouns do not change at all salmon
sheep
Foreign rulings cactus
medium
some nouns adopt foreign rulings cacti
media
Read more about English spelling rules.

Why Is There Confusion over the Plural of Platypus?

Confusion arises over the plural of "platypus" because many believe it is a Latin noun that should be pluralized with an "i" (just like cactus becomes cacti).

Through common usage (even though incorrect), "platypi" is becoming an accepted plural for "platypus." Nevertheless, the safest version to use is "platypuses." (See the difference in Google's Ngram Viewer.)
author logo

This page was written by Craig Shrives.

You might also like...

Help us improve...

Was something wrong with this page?

Use #gm to find us quicker.

Create a QR code for this, or any, page.

confirmatory test