Baseline
The line marking the back boundary of a court, running parallel to the net or end wall.
Definition
In racquet sports such as tennis, the baseline is the line at each end of the court that marks how far back the playing area extends. Players stand behind it to serve, and a ball landing beyond it is out, so the baseline defines the length of the court and shapes much of the rallying that happens from the back of the court.
The word is also used in some team sports for the boundary line behind each goal or basket, for example the line running under the hoop in basketball. In every case it simply names the outer line at the end of the playing surface.
Where you’ll hear “baseline”
Sports that use this term:
Tennis
A singles or doubles racquet sport that blends agility, strategy and stamina on court.
Badminton
A fast indoor racquet sport played with a shuttlecock that rewards agility and touch.
Basketball
A fast, dynamic team sport of running, jumping and quick decisions on court.
Pickleball
A friendly, easy-to-learn paddle sport played on a small court with a solid paddle and a light, perforated ball.
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Rules
- Out of boundsThe rule that a ball or player leaving the marked playing area is out of play and possession is decided at the boundary.
- Foot faultA serving fault called when the server's foot touches the baseline or court before striking the ball.
- LetA call that stops a point and has it replayed without penalty, used across several racket sports.
- Throw-inThe method of restarting football when the ball fully crosses a side line, taken by throwing it back into play.
Techniques
- Topspin ForehandA forehand groundstroke hit with a low-to-high swing that puts forward spin on the ball so it dips and kicks up on landing.
- One-Handed BackhandA backhand groundstroke struck with a single hand on the grip, driving through the ball with a full extension of the hitting arm.
- Tennis ServeThe overhead stroke that starts every point, hit from behind the baseline into the diagonally opposite service box.
- Badminton ClearAn overhead stroke that sends the shuttlecock high and deep to the opponent's back court, resetting the rally or buying time.
- Flip TurnA fast turn in freestyle where the swimmer somersaults at the wall, pushes off on their back and rotates to continue swimming.
Tactics
- Baseline playA patient tennis style built around rallying from the back of the court and constructing points with groundstrokes.
- Doubles formationHow a pair positions itself on court — one up, one back, or both at the net — to control space in doubles.
- Serve and volleyAn attacking tennis tactic where the server follows their serve to the net to finish the point with a volley.
- Offside trapA defensive football tactic where the back line steps up together to leave an attacker offside.
- Negative splitA pacing tactic where an athlete covers the second half of a race faster than the first.
Facilities
- Tennis courtA rectangular marked court, divided across the middle by a net, where tennis is played as singles or doubles.
- Basketball courtA rectangular hard-surfaced court with a raised hoop and backboard at each end where basketball is played.
- Volleyball courtA rectangular court split by a high net over which two teams rally the ball, played indoors or on sand.
- Sports hallA large indoor hall with multi-sport line markings, used for court sports like basketball, volleyball and badminton.
- Padel courtAn enclosed court, much smaller than a tennis court, walled with glass and mesh so the ball can be played off the walls.
Playing surfaces
- Hard courtA rigid acrylic, concrete or asphalt court that gives a true, consistent, medium-paced bounce — the standard multi-use outdoor surface.
- ClayA soft, granular racquet-sport surface of crushed brick, stone or shale that slows the ball, gives a high bounce and lets players slide into shots.
- WoodAn indoor sprung timber or parquet floor — grippy, consistent and lightly cushioned; the classic surface for indoor court sports.
- GrassNatural turf grown on soil — the traditional surface for many field sports and, in tennis, a fast court with a low, skiddy bounce.
- TrailNatural off-road terrain of dirt, rock, roots, grass and mud that varies constantly and rewards surefootedness in trail running, mountain biking and hiking.