Is Octopi the Correct Plural of Octopus?

Sep 8, 2006
Sounds better to me!

Could quite possibly be D. Hope you get to spend some quality time with it before it kills over. I've been wondering since a few months have passed by if the filosus season is in considering the ones everyone got a few months back all seemed to be at their end. Not really a conversation for this thread though.


Aug 18, 2008
Hello, this is my first post. If there is any rule against posting in old threads, let me know!

Darwinishungry;34148 said:
What exactly is the plural form of octopus? I've heard octopusES and octoPI from many different places.
I can give you some information about the Classical Greek and Latin(ized) forms of the word.

It is true that oktopodes (masculine and feminine) and oktopoda (neuter) are the normal (nominative) plurals of the Greek word oktopous, but the funny thing about the word pous ("foot") is that while its true stem is pod- (third declension), it had a shorter stem po- (second declension). This would also apply to its compound words.

The Romans themselves latinized Greek words and treated them as Latin words by giving them Latin endings, so the argument about how octopi is incorrect because it is a latinized Greek word treated as a Latin word was dreamt up by someone unfamiliar with Latin grammar. So, the "mistaken notion" here is the idea that octopi is problematic because it has a Latin ending.

The word polypus ("many foot"), from pous, was latinized and had the shorter stem polypo-. You would think that its plural would be polypodes, but it has the plural polypi.

Octopodes is the plural according to the true stem of the word octopus, but octopi is the latinized plural according to the shortened stem.

Octopi isn't really any more incorrect grammatically than polypi. It's just going by an unusual, but nevertheless existing, shorter form of the word.

On a related note, the Superorder name Octopodiformes uses the true stem (octopod-), but the Family name Octopoteuthidae uses the shorter one (octopo-).

Article said:
A note on the plural form: Fowler's Modern English Usage states that "the only acceptable plural in English is octopuses", and that octopi is misconceived and octopodes pedantic.
And yet it does not seem to have a problem with the plural form polypi.

Article said:
Octopi derives from the mistaken notion that octopus is Latin. It is not. It is (Latinized) Greek, from oktopous (ὀκτώπους), gender masculine, whose plural is oktopodes (ὀκτώποδες).
Yeah, again, this argument was dreamt up by someone unfamiliar with Latin grammar.

The Romans themselves gave latinized Greek words Latin endings, and here is the HTML version of a respected Latin grammar book (Allen and Greenough New Latin Grammar) showing various ways to do so:

Does heroibus, for instance, derive from the "mistaken notion" that heros is Latin? It is not.

How about tigrium, and so on?

And what about polypi?

This "mistaken notion" argument is specious at best.


TONMO Supporter
Staff member
Mar 8, 2004
Thanks for your linguistic kung-fu, and :welcome: to TONMO!

I am neither qualified nor foolish enough to leap (back) into the linguistic smackdown, but I would suggest from the sidelines that we coin the terms "octopedantry" and "octopedantic" for this discussion-- not meaning to make fun of the participants, just the debate itself.

p.s. replying to old threads is usually encouraged, certainly in this case!


Staff member
Sep 4, 2006
Fun discussion and a first to bring up the idea that the Romans were a bit snobbish with their acquisition of Greek words. I guess I will have to allow my (fun) neighbors to use octopi now. They will be so disappointed that I don't object when they try to goad me into making a correction :sagrin:


Colossal Squid
Nov 19, 2002
I'm boring and like to be simple........ I go with the sheep! 1 sheep many sheep: one octopus many octopus!!! That way I don't have to remember podes, podi, pedes, pi or any other p ending!!!!!!!


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