Definition of "grandfather" in English

noun

1. A father of someone's parent.

2. (by extension) A male forefather.

3. (computing) The archived older version of a file that immediately preceded the father file.

verb

1. (transitive) To be, or act as, a grandfather to.

verb

1. (transitive, chiefly US, law) To retain discontinued laws or rules for (an object, individual or organization previously affected by them).