Main Entry: sis·ter–in–law

Pronunciation: \ˈsis-t(ə-)rən-ˌlȯ, -tərn-ˌlȯ\

Function: noun

Inflected Form(s): plural sis·ters–in–law \-tər-zən-\

Date: 15th century

1 : the sister of one's spouse
2 a : the wife of one's brother b : the wife of one's spouse's brother