the ball used in playing the game of racquetball
"He adjusted his grip on the yellow rubber racquetball before serving it down the court."
a game played on a handball court with short-handled rackets
"We spent the afternoon playing racquetball in the gym, hitting the ball back and forth against the wall with our short-handled rackets."
A certain sport, similar to squash, but played with a bigger ball.
"She packed her bag with fresh water and gloves before heading to the court to play a game of racquetball against her brother."