What is the plural form of ethos? I have always thought it was "ethoi," but I'm not sure.
Since there are two reputable seeming answers (one in comments), I though I would sort out which plural is correct: ethoi, ethea or ethe.
Edwin Ashworth in the comments is right to say that the hypercorrect plural is ethoi (as per Wikitionary).
- (hypercorrect) plural of ethos
I would, however, like to define what Wiktionary means by hypercorrect:
hypercorrect Incorrect because of the misapplication of a standard rule; for example, octopi used as the plural form of octopus is hypercorrect because -us → -i is the rule for forming plurals of originally-masculine nouns of the Latin second declension, whereas octopus actually derives from Ancient Greek and has the plural form octopodes consistent with its etymology.
It is important to note that hypercorrect words are explicitly incorrect.
Not ethoi then.
As Uli Troyo has partly explained, this is the contracted form of the Ancient Greek plural.
From the Ancient Greek ἤθη (ḗthē), the contracted nominative plural form of ἦθος (êthos).
From the Ancient Greek ἤθεα (ḗthea), the uncontracted nominative plural form of ἦθος (êthos).
As far as I can tell, there is no semantic difference between the contracted and uncontracted plurals.
Finally, it is worth mentioning that since it has assimilated into English, ethoses is acceptable (and probably far wider recognised), even if it lacks etymological backing.