A style of music characterized by having both metal and punk influence. The term was first coined by the band DOA on the "Hardcore '82" EP, if I'm not mistaken. Unfortunately, it's being taken to extremes by suburban gangbangers who form crews and beat the shit out of people who don't let them karate dance wherever they want to. And they don't have any respect at all, in most cases. Hardcore used to be about unity and brotherhood, but now it's about who has the biggest crew and who dances the hardest. And it's becoming closer and closer to bad death metal with 1-chord breakdowns.
OG hardcore kid: What's up, man? Have you heard this band Gorilla Biscuits? They're rad. Circle pit!
Modern hXc crew kid: Yo dog, my ABC/DEC/WAC/PHUC crews is some gangstaz! Whatup cuz! We's hXc like a mofo. What that kid said?!?! Bust his ass, yo! Awww snap! Breakdown time! *spin kick, flail, windmill*