When I was in college, I had a roommate who was a concert pianist. You could go over to the piano and crunch your hands, toes, elbows down on a dozen notes at once and without looking she could tell you precisely what notes you were playing. Never missed a single one.

You could be standing in the middle of a supermarket or on a sidewalk or whatever and ask her for the e-flat above Middle C and she'd be able to nail it for you.

That's perfect pitch.

I have good relative pitch, meaning I can usually start a song in whatever key I've learned it. And I'm driven crazy by people singing or playing off pitch, but that may be more a function of training than of some innate pitch.

WW