its a word I've heard my American friends use when referring to a tap..
Pretty much sites that give you free BTC for filling a captcha. The faucets themselves gain their money from advertisements on the site. It doesn't pay out a lot, but it is totally free (except for maybe the electricity) and the value of BTC is constantly increasing so it could be worth a lot more later. Personally, I earned more from faucets than mining. Of course, I haven't been mining a lot and my computer only mines 90 Mhash/min.
For a list of free faucets and other ways to gain risk free bitcoins, I'd recommend the link in my description. But there are many other faucets out there, so if you can find more just search around a bit on this site or google.