Basketball is a sport in which two teams of five players each try to score points on one other by throwing a ball through a hoop (the basket) under organized rules.

Since its invention in Springfield, Massachusetts in 1891, it has developed to become a truly international sport. Organized league play originated in the YMCA and early leagues were formed in colleges. Basketball eventually became a professional sport and is one of the few women's sports which developed in tandem with men's. The modern rules for women's basketball become more similar to men's each year. Even though it was originally an American sport, it quickly spread internationally and outstanding players and teams are found today all over the world.

Points are scored for passing the ball through the basket from above; the team with more points at the end of the game wins. The ball can be advanced on the court by bouncing it (dribbling) or passing it between teammates. Disruptive physical contact (foul) is not permitted and there are restrictions on how the ball can be handled (violations).

Through time, basketball has developed to involve common techniques of shooting, passing and dribbling, as well as players' positions, and offensive and defensive structures. While competitive basketball is carefully regulated, numerous variations of basketball have developed for casual play. Basketball is also a popular spectator sport.

While competitive basketball is primarily an indoor sport, played on a basketball court, less regulated variations have become exceedingly popular as an outdoor sport among inner city groups, particularly African-Americans. Examples of these variations include [Streetball] and One-One one Basketball; a variation in which two players will use only a small section of the court (often no more than a quarter of a court) and compete to play the ball into a single hoop. Such games tend to be more physical than competitive indoor basketball, and emphasize individual dribbling and ball stealing skills over shooting and team play.

Outdoor basketball courts are commonly referred to as 'blacktop', a reference to the [asphalt] surface used on many outdoor recreation grounds. This term can apply regardless of the actual surface material used.