But is a triple jump the same as a hop, skip and jump? It seems to me that a hop and a skip are each smaller than a jump.

The triple-jump event is literally described as "a hop, skip, and jump." The three bounding motions are done in a sequence without breaking forward momentum, so "triple jump" is an accurate description of the combination, while "hop, skip and jump" is an accurate description of each of the three bounds individually.