The Collaborative International Dictionary
change-up \change-up\ n. (Baseball) same as change-of-pace.
Syn: change-of-pace, change-of-pace ball, off-speed pitch. [WordNet 1.5] ||
change-of-pace \change-of-pace\ n. (Baseball) a baseball pitch thrown with little velocity when the batter is expecting a fastball; -- called also change-up.
Syn: change-up, change-of-pace ball, off-speed pitch.
Wiktionary
n. 1 An unexpected event. 2 (context baseball English) A pitch thrown with the arm motion of a fastball, but which travels at a much slower velocity because it is released without the fingers adding power to the delivery.
WordNet
n. a baseball thrown with little velocity when the batter is expecting a fastball [syn: change-of-pace, change-of-pace ball, off-speed pitch]
Usage examples of "change-up".
Then a curveball for strike two, and then that change-up, fat and right down the middle, but looking faster than it was so the guy swung early and hit it off the end of the bat instead of the meat, lofting a lazy flyball to left, where Mel Nelson caught it without taking a step.