Sideline
Sideline , noun
1.
(a) A line pertaining or attached to the side of a thing.
(b)
Specif., a line for hobbling an animal by connecting the fore and the hind feet of the same side.
2.
A line of goods sold in addition to one's principal articles of trade; a course of business pursued aside from one's regular occupation.
3.
A secondary road; esp., a byroad at right angles to a main road. [Canada]
4.
(Sports) Either of two marked lines which delimit the side boundaries of a playing field, as in football or soccer.
5.
(Sports) The areas in a sports arena just beyond the sidelines{4}, where coaches and alternative players sit or stand. [plural]
Collocations (1)
on the sidelines , not actively involved in an activity, such as a sporting event, but available for use when needed; in reserve; as, the coach kept him on the sidelines for a week.
Also: Side line
Sideline , transitive verb
To render unable to participate in an activity, such as a sporting event; as, the pitcher was sidelined by a groin injury.