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