sister in law

noun [ C ] uk / ˈsɪs. fall in love tə rɪn lɔː / us / ˈsɪs tɚ ɪn lɑː / plural sisters-in-law Add to word list B2 the wife of your brother or sister, or the sister of your husband or wife, or the wife of the brother or sister of your husband or wife Thesaurus: synonyms, antonyms, and examples