Comment by TZubiri

This is a common theme, gambits are such depending on what your level and calculation depth is.

The queen's gambit opening (almost inarguably a gambit as it is part of a well accepted name of a second move), really isn't a gambit in the sense that you can always recover the pawn, however it is a gambit in the sense that you temporarily give it up.

If we were particularly short sighted, no doubt, responding to an early white bishop threat on g5 or b5 with a knight on f6 or c6 would look like a gambit, as we are sacrificing the knight, but lo and behold, we regain the minor piece afterwards with xf6 or xc6!

The distinction would be whether the gambit or sacrifice is solid or refutable. But it is in both cases a sacrifice.