Board Thread:Speculation House/@comment-68.186.83.101-20130601225528/@comment-26397825-20160120092212

Uh...Yang called Qrow her Uncle because he is Raven's brother, and Raven is her mother. The brother of your mother is called your uncle. So no, it's not wrong.

Ruby called Qrow Uncle because she likes him enough to call him uncle, despite there being no blood relation between them.