A Sub-genre of modern music that is defined by a lot of black clothes, metal music, and shaggy black hair. It is a combination of the words metal and hardcore. The X in the middle is crucial, because we all know you're not hardcore if you spell without X's in the middle of everything.
Scene Kid: "Look at Josh moshing over there! He's so metalXcore!"
by emoemilyXcore March 30, 2006