Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Co-vary is regular. It follows the -ies Conversion rule.
Use plural verbs: "The co-varies are ready" (not "is ready").
Yes. The plural co-varies is standard across all English variants.
The word co-vary follows the standard English pluralization rule. When forming the plural, co-vary becomes co-varies. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why co-vary becomes co-varies helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using co-varies in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The co-varies are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.