Why is the plural of 'nemesis' "nemeses" and not 'nemesii'?

and how does one pronounce "nemeses" different from "nemesis"?

  • Related: What are the correct plural forms of “penis”?
    – herisson
    Dec 16, 2016 at 10:30
  • 1
    Why is the plural of is are, and not ii? Why is the plural of sheep sheep and not sheepi? Why is the plural of child children and not childi? Why is the plural of car cars and not cari? And why are we now asking questions that make no sense, and even if they did, knowing the answer would gain us nothing at all? Whether or not we know why the plural of mother is not motheri is entirely irrelevant to the fact that we know what the correct form is. So just use it, then, rather than wondering why actual isn't imaginary and imaginary isn't actual.
    – RegDwigнt
    Dec 16, 2016 at 11:37
  • Ultimately related.
    – tchrist
    Dec 16, 2016 at 12:54

1 Answer 1


Nemesis is directly taken from Latin (which borrowed it from Greek). In Latin, almost all words ending in -is have -es as plural form. You will see the -ii plural form only for nouns which end in -ius.

You can hear the difference between the pronunciation here; nemesis rhymes on this and nemeses rhymes on these.

  • Just adding something to the fire: In english you always get the other idioms rules wrong. Némesis is a name, borrowed from Greek. We agree. In Latin, the plural is formed adding an "S". When the last word is a consonant (not S) you can't add an S. The solution is to add "ES" to the end. So, when you have "aguja (needle)" it becomes "agujas (needles)" but when you have "cajón (drawer)" it becomes "cajones (drawers)". Némesis ends in S as singular so in plural does not need an S (language rule). Same as in París, Tenis and Némesis. To change "is" for "es" is nonsensical in Latin and Spanish.
    – Billeeb
    Feb 28, 2018 at 11:28

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