brother-in-law /ˈbrʌðɚrənˌlɑː/ noun plural brothers-in-law /ˈbrʌðɚzənˌlɑː/ plural brothers-in-law /ˈbrʌðɚzənˌlɑː/ Learner's definition of BROTHER-IN-LAW
[count]
1
: the brother of your husband or wife大伯子;小叔子;大舅子;小舅子
2
: the husband of your sister姐夫;妹夫