kai-. Important derivatives are: hot [<---so true] and heat.
Extended form *kaid-.
1. a. HOT, from Old English hat, hot, from Germanic *haitaz;
b. HEAT, from Old English haetu, from Germanic *haiti-.

this is from the american heritage dictonairy. isn't appropiate?? *laughs* so what if it's about a *confuzzled look* hat... it says 'hot', don't it??