What is a mother? Is it merely a woman who gives birth, or is it something more?

If a woman has children but doesn't know how to love them, because she doesn't know what love is, is she still just as much a mother to them?

For the record, I think that most mothers really do love their children and do a decent job, though of course no one is perfect.

Maybe the definition is more clear-cut than I'm making it out to be. Maybe it's simply a woman who is a biological parent. But I'd like to hear what others here think being a mother really means.