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

Doncic had not yet reunited with his teammates when coach JJ Redick spoke before the game, but the Lakers looked forward to getting him back on the sideline.

From Los Angeles Times • Apr. 18, 2026

But she said the U.S. can’t let the problem in the strait sideline the nuclear issues that are central to the conflict.

From The Wall Street Journal • Apr. 11, 2026

Charlisse Leger-Walker, a transfer from Washington State, spent the year on the sideline recovering from an anterior cruciate ligament injury.

From Los Angeles Times • Apr. 4, 2026

In an interview with reporters on Wednesday, the St. Louis Fed president, Alberto Musalem, said he supported the policy of sticking to the sideline for now.

From MarketWatch • Apr. 2, 2026

From the outset, he ran back and forth on his sideline, barking at his players in a hoarse bellow: “Man on! Man on! Drop it! Drop it! Turn! Turn! Turn!”

From "Outcasts United: An American Town, a Refugee Team, and One Woman's Quest to Make a Difference" by Warren St. John