[ sahyd-lahyn ]
/ ˈsaɪdˌlaɪn /


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.
  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.
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), side·lined, side·lin·ing.

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

An Americanism dating back to 1685–95; side1 + line1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for sidelines

British Dictionary definitions for sidelines (1 of 2)

/ (ˈsaɪdˌlaɪnz) /

pl n

sport the area immediately outside the playing area, where substitute players sit
the peripheral areas of any region, organization, etc

British Dictionary definitions for sidelines (2 of 2)

/ (ˈsaɪdˌlaɪn) /


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

verb (tr)

to prevent (a player) from taking part in a game
to prevent (a person) from pursuing a particular activity, operation, career, etc
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Idioms and Phrases with sidelines


see on the sidelines.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.