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