Good, I am glad we caught that... I think some canopy tours include zip-lines, but technically a canopy is justthe word for the tree tops in a rainforest. So, I have seen tours (in Costa Rica) advertise a "canopy tour" but all it is is a hike along some trails with bridges that take you over the "canopy" of the rainforest (it starts at the top of a ravine and goes side to side and down). It was actually very boring and I was very disappointed after going all that way that we missed some of the cool wildlife you can see in Costa Rica.
A zip-line is an actual wire you hook up to and ride on rollers from point to point. I think one of the first zip-line tours was in Costa Rica, and they used the word Canopy in the tour, and that was where the confusion started. Now there are zip lines everywhere.