Racquetball is an indoor sport. Two or four players go into a room-like court and hit a small, very bouncy rubber ball with a short strung racquet. All four walls, and often the ceiling, are in play — the ball can fly everywhere. It looks a cousin of squash, and students often mix them up, though actually they are different games: the racquet is different, the ball is much bouncier, and the rules are not the same. The spelling racquetball is the usual American one. It grew up in the United States in the mid-20th century and still feels like an American gym sport. In Britain you may also hear racketball for a related game. It is ordinary sports English, not a fancy word.