'Father in law' in the Bible

And it was told to Tamar, saying, Behold, your father-in-law goes up to Timnah to shear his sheep.

When she was brought forth, she sent to her father-in-law, saying, I am with child by the man whose things these are. And she said, Please observe. Whose things are these, the signet, and bracelets, and staff?