A hybrid bicycle is one designed to be sturdy enough to be for useful for urban commuting, yet light and fast enough to suitable for high speed travel on the open road. It is sort of a compromise between an off-road boondocks machine, and a flat-out racer, but not really optimized for either application. They used to be called "touring" bikes, before the marketing euphemizers got a hold of the concept.

My own bike is in this category, a twenty-year old Fuji Sagres 12-speed. Everything on it except the frame, handlebars and saddle has been replaced at least once, and that is starting to get some rust. It had 15000 klicks on it when the odometer broke 10 years ago. I guess I'll have to replace it eventually, but I'm not looking forward to buying a hybrid. A bit too yuppified for my taste, and they're ugly.