ultramafic

[ uhl-truh-maf-ik ]

adjective

, Geology.

1. ultrabasic.

ultramafic

/ ŭl′trə-măf′ĭk /

1. Containing mainly mafic minerals. Used of igneous rocks and often used interchangeably with ultrabasic. Dunite is an ultramafic rock.

Word History and Origins

Origin of ultramafic¹

First recorded in 1940–45; ultra- + mafic