• synonyms


noun, plural gab·bros. Petrology.
  1. a dark granular igneous rock composed essentially of labradorite and augite.
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Origin of gabbro

< Italian; akin to Latin glaber smooth
Related formsgab·bro·ic [guh-broh-ik] /gəˈbroʊ ɪk/, gab·bro·it·ic, adjectivegab·broid [gab-roid] /ˈgæb rɔɪd/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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Historical Examples of gabbro

British Dictionary definitions for gabbro


noun plural -bros
  1. a dark coarse-grained basic plutonic igneous rock consisting of plagioclase feldspar, pyroxene, and often olivine
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Derived Formsgabbroic or gabbroitic, adjective

Word Origin for gabbro

C19: from Italian, probably from Latin glaber smooth, bald
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for gabbro


type of igneous rock, 1837, from Italian (Tuscan) gabbro, from Latin glaber "bare, smooth, bald" (see glad).

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Online Etymology Dictionary, © 2010 Douglas Harper

gabbro in Science


  1. A usually dark, coarse-grained igneous rock composed mostly of plagioclase feldspar and clinopyroxene, and sometimes olivine. Gabbro is the coarse-grained equivalent of basalt.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.