1. a boundary line along the side of a playing field or court
Usage: sports
2. an activity or business pursued in addition to one’s main job
3. the area along the side of a sports field where coaches and substitutes stand
Usage: sports

1. to remove a player from active participation in a game
Usage: sports
2. to remove someone from their usual activity or position

Examples

• The ball went out of bounds when it crossed the sideline.
• She runs a catering business as a sideline to her teaching job.
• The coach paced nervously along the sideline during the game.
• The injured quarterback was sidelined for three weeks.
• Budget cuts sidelined the new construction project.
• Parents cheered from the sidelines during the soccer match.
• His photography sideline became quite profitable over time.