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)

sidelines, present (3rd person singular) sidelined, past participle, past sidelining present participle

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

Other Word Forms

Conjugated Forms

Present

• has sidelined
  perfect 3rd person singular
• have sidelined
  perfect
• am sidelining
  progressive 1st person singular
• have been sidelining
  perfect progressive
• has been sidelining
  perfect progressive 3rd person singular
• sidelining
  participle
• is sidelining
  progressive 3rd person singular
• sidelines
  singular 3rd person
• are sidelining
  progressive

Past

• had sidelined
  perfect
• had been sidelining
  perfect progressive
• sidelined
  participle
• were sidelining
  progressive plural
• sidelined
  simple
• was sidelining
  progressive singular

Future

• will sideline
  simple
• will have sidelined
  perfect
• will be sidelining
  progressive
• will have been sidelining
  perfect progressive

Etymology

Origin of sideline

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

Example Sentences

"Then a few seconds later I just passed out on the sideline," she says.

From BBC • May 31, 2026

The two candidates who finish in first and second place in the primary will advance to the November general election, leaving the third-place finisher on the sideline.

From Los Angeles Times • May 29, 2026

He is not a demonstrative individual, in news conferences or on the sideline.

From BBC • May 3, 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

Victor and Gino slid for the same ball near our sideline and got tangled up.

From "Tangerine" by Edward Bloor