sister-in-law

My sister-in-law, who is married to my older brother, organized the family reunion.

(Chinese) 我的嫂子，也就是我哥哥的妻子，组织了这次家庭聚会。

I went shopping with my husband's younger sister, my sister-in-law, to buy a gift.

(Chinese) 我和我丈夫的妹妹，也就是我的小姑子，一起去逛街买礼物。