Definition from Wiktionary, the free dictionary
Probably alteration of change of pace.
- (baseball) 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.
- The pitcher had a devastating change-up.
- (by extension) An unexpected event.
- This RFQ is a real change-up.
- (slower than expected baseball pitch): change of pace