I’m often curious about the word lady. Especially the fact that sometimes it’s Lady.
It’s an interesting word in that it’s both a common noun and a formal title. Its use as a title is older than its use as a polite word to refer to a woman, dating back to the 13th century. Still it apparently had quite humble origins, seemingly originally meaning one who kneads bread, from hlaf (bread, where we get the word loaf from).
The word became a fairly common address for any woman at the end of the 19th century, returning to its more everyday, bready roots.
Not completely though, as it’s still a somewhat formal form of address. It’s funny though, that we don’t use a word like lord to refer to men (though of course some people use sir). Maybe it’s a way to keep women restricted to a certain way of behaving, to “protect” them from the more vulgar world. Except of course, men don’t have to be “protected” and can do what they want without having to worry about living up to being lords.
Of course the essential Anglophone politeness inevitably ends up making all this absurd. That’s why ladies can mean wives of lords, and also the toilet.