hard-rock
[hahrd-rok]
adjective
(loosely) of or relating to igneous or metamorphic rocks, as in mining (hard-rock mining) and geology (hard-rock geology).
Compare soft-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