Ball

A ball was an object, usually spherical, that could be used in sporting events or as a simple toy.

A 20th century sport, basketball used a similarly named ball. This sport was still played, at least informally, in 2154. 

The American sport of football, not to be confused with football, used an ellipsoid shaped ball, named after the sport. 

Soccer was a sport that used a ball one would kick on the ground. 

Racquetball was a sport that by the 24th century used small metal rackets and a small green, sometimes glowing, ball. 

The sport of water polo also used a ball. Jonathan Archer had his water polo ball aboard Enterprise, though it rarely saw its intended use. (Star Trek: Enterprise)

In 2267 when Uhura had been altered by Nomad and was speaking in Swahili, Nurse Chapel had her say the line "The dog has a ball," a phrase that took her a few tries. She followed it up by stating that "the ball is blue."

Benjamin Sisko kept a baseball on his desk aboard Deep Space 9 and encouraged an interest in the game of the same name.