noun
plural -lines
[count] a line that marks the outside edge of a sports field or court
the space outside the area where a game is played on a field or court - usually plural
a job that is done in addition to your main job
verb
-lines; -lined; -lining
[+ obj] :to prevent (a player) from playing in a game especially because of injury, illness, etc. - usually used as (be) sidelined
US