feeling dotty

I'm excited for polka dots this fall, mainly in the forms of a pretty blouse (J.Crew) and tights. The other day a ten year-old asked me why they are called polka dots. At first I had no words, then all I could come up with was polka dancing (which seriously mocks such a classic pattern). This is the kind of thing I'd like to know. 

For now, though, I'll just have sweet polka dotted dreams. Two days left of September! How could it be?!