Noisecore is a term normally attributed to fast, aggressive, lo fi and often incomprehensibly noisy hardcore or grindcore with extremely short tracks. It grew out of the hardcore and early grindcore scenes of the mid to late 80s and became somewhat of a subgenre of its own.

Some modern post-hardcore bands have also been labeled as noisecore, and as such, the term is now interchangeably used to refer to a hybridization of noise rock and post-hardcore, characterized by the use of dischordant, clashing tones, feedback and unconventional instrumental technique.

See http://www.cfprod.com/noisecore/noisecore.htm for a list of proper noisecore groups compiled by Mikko Aspa of Nihilist Commando, Pain Nail, etc.

Noisecore is also used as synonym of chaotic hardcore/mathcore.