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