<P> The key, officially referred to as the free throw lane by the National Basketball Association (NBA) and the National Collegiate Athletic Association (NCAA), the restricted area by the international governing body FIBA, and colloquially as the lane or the paint, is a marked area on a basketball court surrounding the basket . It is bounded by the endline, the free - throw line and two side lines (freebody lines), and usually painted in a color different than the rest of the floor . It is a critical area on the court where much of the action takes place in a game . </P> <P> Dimensions of the key area have varied through the history of the game . Starting with 2010 FIBA's rule amendments (first implemented after the 2010 FIBA World Championship), it is rectangular for all games, being 16 feet (4.9 m) wide for both NBA and FIBA keys, while NCAA keys are narrower at 12 feet (3.7 m). Prior to 2006, the key in FIBA - sanctioned tournaments was trapezoidal in shape . </P> <P> The most - commonly enforced rule on the key is the "three seconds rule" in which a player from the offensive team is prohibited from staying on the key for more than three seconds, or else the player's team will lose possession of the ball . Another rule enforced is the lane violation in which players from both teams are prohibited to enter the lane until after the free - throw shooter releases the ball from his hands . A recent innovation is the introduction of the restricted area arc directly underneath the basket where the defending player cannot force an offensive foul on the opposing player . </P> <P> Each level of play has different specifications for the size and shape of the key: in American leagues, where the basketball court is measured in imperial units, the shape is rectangular, while in FIBA - sanctioned events, which use the metric system, the shape was trapezoidal, before being changed to a rectangle as well . In addition to the bounding rectangle, the key includes a free - throw circle at its "head" or "top". </P>

Basketball how long can you stay in the paint