1. the lines marking the side boundaries of a playing field or court
Usage: sports
2. the area along the side of a playing field where spectators, coaches, and substitutes stay
Usage: sports
3. a position of not being actively involved in something
Usage: figurative

1. to remove someone from active participation; to bench or exclude

Examples

• The ball went out of bounds past the sidelines.
• The coach paced nervously along the sidelines during the game.
• She felt frustrated watching from the sidelines while others made decisions.
• He runs a consulting business as a sideline to his teaching job.
• The injury will sideline the star player for several weeks.
• Parents cheered from the sidelines at the soccer match.
• The controversy has sidelined her political career temporarily.