Tess had nearly overtaken her when the speed of her brothers-in-law brought them so nearly behind her back that she could hear every word of their conversation.

I retired to the back porch with my two brothers and brother-in-law, and sat down in a rocking chair with a sigh.

The members of an extended family are related by blood (grandparent, parents, children, brothers, sisters, etc.) or by marriage (husbands, wives, mothers-in-law, etc).