岳父 refers to one's father-in-law. He is the father of one's spouse.
Topic 1.1: 1.1 Families and Communities in China
岳父 (yuèfù) cheat sheet for homework
岳母 (yuèmǔ): One's mother-in-law.
丈夫 (zhàngfu): One's husband.
亲家公 (qìnjiāgōng): A term used to refer to one's father-in-law in a more formal or respectful way.