adj, noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   A rock with such properties.

Adjective

1. 1
   Describing igneous rocks that contain magnesium and iron and only a very small amount of silica, such as are found in the Earth’s mantle.

Synonyms

All synonyms

ultrabasicultrabasic

Etymology

From ultra- + mafic.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.