Ok, I've reading this forum for a while now and I still haven't figured out what a century is.. Could somebody please tell me..

I was just thinking that would it be a bad idea to make a vocabulary for these words and make it like a sticky thread or something or am I just the only one who doesn't know all these words. Like earlier I was very confused with clipless and clip-in pedals. And how about that LBD (local bike dealer?) or LBS (local bike shop??)?? And STD and SPD .. No, but seriously, it would make my life that bit easier again..
thanks girls, you are great!