all these terms get coined by music journos. don't need to ask on forums, just read the rags (magazines for the no potato in mouth proletariat - i can't spell).
read enough pitchfork, you may evolve into some indie musician
read enough kerrang, you become a metal god
read enough Q, you start on the britpop movement
read enough rolling stone, welcome to the world of rock n roll
it's pop culture you dolts, and you're breathing it in everyday.