CCs: not the e-mail kind

So, I’ve been looking at scooters, but I feel I need a primer in powered cycle geekery before I can really shop. I don’t know what a cc is for example, except that somehow it equates to horsepower or something such that more cc’s mean faster speed. I’ve tried googling for a scooter shopper/buyer guide, cc to mph ratio, how to buy, etc…no luck in google. So, general request…does anyone know of a site that could help me learn the basics of what I’m looking for and how to know if I’m getting it?