n. A grey intrusive igneous rock composed mostly of plagioclase feldspar, biotite, hornblende and/or pyroxene.
the GNU version of the Collaborative International Dictionary of English
n. An igneous, crystalline in structure, consisting essentially of a triclinic feldspar and hornblende. It includes part of what was called greenstone.
The Century Dictionary and Cyclopedia
n. The name given by Haüy to a rock included among those varieties which had before that time been generally designated by the name greenstone.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a granular crystalline intrusive rock
Word Usage
"Intrusive igneous rocks such as diorite, gabbro and granite solidify below the Earth's surface while extrusive igneous rocks such as basalt, obsidian and pumice solidify on or above the surface."