I'm not a display pilot, never have been. You are pretty much on the money. A gate is a position in space (top of a loop, for example) with associated parameters (height and speed, most usually). So, at the top of a loop the pilot/crew will need to check that they meet those parameters to know if they have sufficient room to complete the manoeuvre before committing nose low. Other manoeuvres may simply require an adjustment (heading, bank, pitch, throttle).
Layman's explanation. I'm sure they'll be another along in a minute.