foul line

Short definition from Wiktionary

Noun

1. 1
   A line from which a player takes a free throw
2. 2
   One of the two lines on the edge of a field marking the area inside which a fair ball may be hit.
3. 3
   A line between the lane and the approach, which the bowler must not cross.
4. 4
   In long jump, a line before which the jumper must start their jump with no part of the foot touching the line.