A line call in tennis is a decision made by an umpire in tennis on whether the ball has landed in or outside bounds. There are nine line umpires on court and one chair umpire to officiate the match. The line umpires make a line call in the falling scenarios:
Baseline – The baseline is the line behind which the player stands and serves. It is the furthest line from the net.
Centre Service Line – A line passing exactly in the centre of the tennis court that is also a part of the service box is the centre service line.
Alley or Tramlines or Side lines – The two vertical bands on either side of the tennis court is called the alley. If a ball lands within the alley in a singles match, it is out. However, it is considered within bounds in doubles.
Service line – It is a part of the service box that passes horizontally in the centre on either side of the court.
Line calls should be made promptly by the line umpire. Any late calls can be revolted by the player or result in the entire being replayed. A line umpire must be loud and clear while calling the decision. The chair umpire has the authority to reverse the decision of a line umpire. A player can also challenge the call of a line umpire which is later assessed by electronic line calling system.
Line call in tennis is thus forms the basis of vital decision making as the match progresses.