Wiktionary
ball machine
n. (context tennis English) A machine that shoots tennis balls out of a pipe.
Usage examples of "ball machine".
He had leaned his tall angular body against the Skee-Ball machine and wrapped his arms around the broom-handle as though it were a girl at a dance.
The jittery pill-popper turned his attentions to a pin-ball machine inside the entrance.
From the beamed ceiling hung some old lanterns and a pin-ball machine stood abandoned in one corner.