What is (a) To carry over, or back, as type, from one line or page into the next after, or next before. (b) To extend the contents of (a line, column, or page) into the next line, column, or page called?

overrun — (Print.) (a) To carry over, or back, as type, from one line or page into the next after, or next before. (b) To extend the contents of (a line, column, or page) into the next line, column, or page. (Webster's 1913.)