[side.line] n (1862) 1: a line at right angles to a goal line or end line and marking a side of a court or field of play for athletic games
2. a: a line of goods sold in addition to one's principal line b: a business or activity pursued in addition to one's regular occupation 3 a: the space immediately outside the lines along either side of an athletic field or court b: a sphere of little or no participation or activity--usu. used in pl.
[2]sideline vt (1943): to put out of action: put on the sidelines