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