Ahhh, I see the problem. I had incorrectly assumed you were talking about ATP synthase, based on my very flimsy and rushed reading of your comment. Incidentally, I am of the camp that considers ATP synthase part of the ETC, but my critique of you was still based on my misperception of what you were trying to say.
Thanks for correcting my correction, science is hard and biology is confusing!

Almost, but not quite. The proton gradient refers to the difference in concentration of H+ on each side of the membrane. It's ostensibly what allows for the ETC to transport those protons in the first place, by following their own gradient and harnessing some energy in the process to make ATP.