Yep. In the strictest sense, float is the degree of twist of the cleat (and therefore your foot) inside the "clip" mechanism before it unclips. (So higher float, the further your foot can travel without unclipping.) What that translates into is how much your knee and ankle can move. I think SPDs (at least the ones I have, the M540s) have about 5 degrees of float. I need a bit more, according to my fitter.

Look-style pedals (and I think this is true for all of them) have "adjustable" float, in the sense that you can use the same pedal with different cleats that give different float.