sideline

American  

[sahyd-lahyn] / ˈsaɪdˌlaɪn /

noun

sidelines plural

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.

---

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

---

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

Inflected Forms

Nouns

• sidelines
  plural

Participles

• sidelining
  present
• sidelined
  past

Conjugated Forms

Present

• sideline
  simple
• sidelines
  simple
• have sidelined
  perfect
• has sidelined
  perfect
• are sidelining
  progressive
• am sidelining
  progressive
• is sidelining
  progressive
• have been sidelining
  perfect progressive
• has been sidelining
  perfect progressive

Past

• sidelined
  simple
• had sidelined
  perfect
• was sidelining
  progressive
• were sidelining
  progressive
• had been sidelining
  perfect progressive

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

“All personnel sitting in the booth must abide by policies that prohibit the use of electronic devices other than league-issued equipment such as a Microsoft Surface Tablet for the Sideline Viewing System.”

From Los Angeles Times • Sep. 16, 2025

Sideline reporters play a key role in American football broadcasts by giving live updates from on or near the field.

From BBC • Nov. 17, 2023

Sideline reporters described how it feels to cover a top-two matchup.

From New York Times • Nov. 5, 2022

Sideline mask-wearing previously had been recommended for players during games but not required; it was required of players before and after games.

From Washington Post • Nov. 23, 2020

New Era Official NFL Sideline Knit Cap: Support the Seahawks and stay warm in style with the same cap that the team wears during games.

From Seattle Times • Nov. 19, 2019