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