A musical genre.
The ending derives from hard core, the most active, committed, or unyielding members of a group or movement, which derives from its sense in British English of rubble and other stony material used for the foundations of buildings. The term, usually as hard-core or hardcore) also refers to pornography of an explicit kind (contrasted with softcore, which is suggestive or erotic but not explicit).
The musical form called hardcore is a uncompromising, experimental, and harsh form of techno. Other terms for musical genres have been invented in the eighties and nineties on its model: queercore, a punkish and aggressive musical style favoured by some young homosexuals; loungecore, a dismissive term for an easy-listening style with no strong character; grindcore, a type of fast heavy metal music incorporating harsh noise; and thrashcore, a noisy, thrashing punk style.