Avunculocal residence is a cultural norm in which a married couple move in with the husband's mother's brother.
Sound pointless? It's not! (Well, maybe a little -- you decide). This is the kind of stuff that makes anthropology so cool.
In a matrilineal culture, lineage passes through the females. But power and leadership resides in the males. (Humans are weird that way). So when a female has children, they belong to her lineage, and not her husband's. (Her husband isn't part of the culturally recognized family). But her male children need someone of her lineage to teach them the manly arts of leadership, owning land, and warfare. So, who is part of her family? Her brothers, of course. So when a young man reaches adolescence, he moves in with his uncle. At the time of marriage, he will bring his wife to live with his uncle.
Note that, although the bride moved in with her husband, the children the husband will sire aren't of the husband's family. The male children will eventually travel back from whence their mother came, to live with their uncles.