One's spouse's father. / (dated) A stepfather.

The man from whom one inherits half of one's DNA and from whom men inherit their Y chromosome.

One who represents, behaves as, or is regarded as equivalent to a father for another person or group of people.

The chairperson or the senior shop steward of a trade union chapel (branch) in UK printing and journalism.

God or God the Father (in various Christian churches) / The title of the Pope of the Catholic Church.

A man who has adopted a child, as opposed to a biological father.

A holiday in celebration of fatherhood, or to honor fathers, celebrated on the third Sunday of June in most of the world's countries. See Wikipedia:Father's Day:Dates.

(chiefly US) Any of the men who were responsible for the founding of the United States of America. Chiefly used to refer to political leaders who drafted the Declaration of Independence and the United States Constitution, and to military leaders who fought in the American Revolutionary War.

A man who founded something.

(Christianity) The devil; Satan. / Herodotus, so called because of his controversial works.