- a line at the side of something.
- a business or activity pursued in addition to one's primary business; a second occupation.
- an additional or auxiliary line of goods: a grocery store with a sideline of household furnishings.
- sidelines, the position or point of view taken by a person who observes an activity or situation but does not directly participate in it.
- to render incapable of participation, especially in anything involving vigorous, physical action, as a sport: An injury to his throwing arm sidelined the quarterback for two weeks.
Origin of sideline
- sport a line that marks the side boundary of a playing area
- a subsidiary interest or source of income
- an auxiliary business activity or line of merchandise
- to prevent (a player) from taking part in a game
- to prevent (a person) from pursuing a particular activity, operation, career, etc
also side-line, "line on the side of a fish," 1768; "lines marking the limits of playing area" (on a football field, etc.), 1862, from side (adj.) + line (q.v.). Meaning "course of business aside from one's regular occupation" is from 1890. Railway sense is from 1890. The figurative sense of "position removed from active participation" is attested from 1934 (from the railway sense or from sports, because players who are not in the game stand along the sidelines). The verb meaning "put out of play" is from 1945. Related: Sidelined; sidelining.