姑子;弟媳
Sister-in-law \Sis"ter-in-law`\, n.; pl. {Sisters-in-law}.
The sister of one's husband or wife; also, the wife of one's
brother; sometimes, the wife of one's husband's or wife's
brother.
sister-in-law
n : the sister of your spouse
[also: {sisters-in-law} (pl)]