sideline

Short definition from Wiktionary

Noun

1. 1
   A line at the side of something.
2. 2
   Something that is additional or extra or that exists around the edges or margins of a main item.
3. 3
   A line for hobbling an animal by connecting the fore and the hind feet of the same side.
4. 4
   A line defining the side boundary of a playing field. Used in Canadian football, field lacrosse and basketball.
5. 5
   The area outside the playing field beyond each sideline.
6. 6
   The outside or perimeter of any activity.
7. 7
   A secondary road, especially a byroad at right angles to a main road.
8. 8
   A side hustle.

Verb

1. 1
   To place on the sidelines; to bench or to keep someone out of play.
2. 2
   To remove or keep out of circulation or out of the focus.