sideline

American  

[sahyd-lahyn] / ˈsaɪdˌlaɪn /

noun

1. a line at the side of something.

2. a business or activity pursued in addition to one's primary business; a second occupation.

3. an additional or auxiliary line of goods.

   a grocery store with a sideline of household furnishings.

4. Sports.

   1. either of the two lines defining the side boundaries of a field or court.

   2. sidelines, the area immediately beyond either sideline, where the substitute players sit.

5. sidelines, the position or point of view taken by a person who observes an activity or situation but does not directly participate in it.

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verb (used with object)

sidelined, sidelining

1. 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.

sideline British  

/ ˈsaɪdˌlaɪn /

noun

1. sport a line that marks the side boundary of a playing area

2. a subsidiary interest or source of income

3. an auxiliary business activity or line of merchandise

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verb

1. to prevent (a player) from taking part in a game

2. to prevent (a person) from pursuing a particular activity, operation, career, etc

Etymology

Origin of sideline

An Americanism dating back to 1685–95; side ¹ + line ¹

Example Sentences

“I live 3 miles away from the school that I coached at for 20 years, and the last time I went to a game…there was not one kid on the sideline that I knew.”

From The Wall Street Journal • May 10, 2026

Even after Redick’s sideline dust-ups, Reaves knows he can still talk it through with the coaching staff.

From Los Angeles Times • May 9, 2026

Collins came dressed as George Washington, a sideline that he started at Fourth of July celebrations at his church 25 years ago and has continued to this day.

From Slate • Apr. 28, 2026

A well-off grain dealer in those days, with a sideline as an art collector, fragments of his pre-war life survive in the paintings and sculptures by Ukrainian artists dotted around the bunker.

From BBC • Apr. 27, 2026

I remember one night, I nearly quit because I had hit the numbers for ten cents—the first time I had ever hit—on one of the sideline bets that I’d made in the drugstore.

From "The Autobiography of Malcolm X" by Alex Malcolm X;Hailey