Lady? It's a term intended as a politeness to strangers, and one used by most folk. I expect most of us were raised as kids to do it as a matter of course. But it's always funny to me when Mums in shops say to their kids something like: "You're in the lady's way" or "Don't run into the Lady" when referring to me - as I'm very much not a lady! Pretty much a complete hippy scruff-bag actually, who runs around in unladylike boots and tatty old second hand clothes. In the U.S. I believe it's customary to refer to strangers as Sir or Ma'am, neither of which in such instances imply any kind of genuine recognition of, or deference to, another's supposed social status. Similar thing with 'lady' or 'gentleman'. I'll often casually refer to guys as 'gents' too, especially if they're older, like "the gent with the pipe and glasses" or even "that homeless gent by the railings"..