This noun follows the standard English plural rule: simply add -s to the singular form.
Sister-in-law is regular. It follows the Standard -s rule.
Use plural verbs: "The sister-in-laws are ready" (not "is ready").
Yes. The plural sister-in-laws is standard across all English variants.
The word sister-in-law follows the standard English pluralization rule. When forming the plural, sister-in-law becomes sister-in-laws. This follows the Standard -s pattern, which is one of the most common plural rules in English.
Understanding why sister-in-law becomes sister-in-laws helps with spelling and pronunciation. This noun follows the standard English plural rule: simply add -s to the singular form.
When using sister-in-laws in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The sister-in-laws are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.