Who knows what these things are anyway? Head tube, stem, top tube, down tube, fork, seat stay, chain stay, shifters, tire, rim, spoke, saddle, seat post brake levers, cassette, front derailleur, rear derailleur, crank pedal . . . it can be overwhelming!
If you're new to cycling you will want to be able to geek out with your training buddies. Better learn your nomenclature! Check out this handy animation to get a handle on describing your bikes basic parts and components.