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