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