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