hard-rock

[ hahrd-rok ]
/ ˈhɑrdˌrɒk /

adjective

(loosely) of or relating to igneous or metamorphic rocks, as in mining (hard-rock mining) and geology (hard-rock geology).

Origin of hard-rock

First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019