Yes, I did explain its meaning. I don't think I'd ever expect children under the age of about sixteen to know the word. I wouldn't necessarily be surprised if they did, but I wouldn't expect it.
She is well-informed about human reproduction and menstruation, and about such related things as homosexuality and abortion. We bought her three books recommended by DD2, who works for a charitable youth drop-in centre in Leith, when she was nine. She 'devoured' them. At that time she was particularly interested in how babies are born (as was DD1). The biology is fascinating.
DD2, who has lots of contact with young city kids from the age of twelve, often remarks about their ignorance about such matters. Presumably they don't learn much at school (not necessarily because it isn't taught, but because they don't/can't pay attention), and perhaps their parents don't discuss such things with them.