gabbro

American  

[gab-roh] / ˈgæb roʊ /

noun

Petrology.

plural

gabbros

1. a dark granular igneous rock composed essentially of labradorite and augite.

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gabbro British  

/ ˈɡæbrəʊ /

noun

1. a dark coarse-grained basic plutonic igneous rock consisting of plagioclase feldspar, pyroxene, and often olivine

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gabbro Scientific  

/ găb′rō /

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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Other Word Forms

• gabbroic
  adjective
• gabbroid
  adjective
• gabbroitic
  adjective

Etymology

Origin of gabbro

< Italian; akin to Latin glaber smooth

Compare meaning

How does gabbro compare to similar and commonly confused words? Explore the most common comparisons:

• gabbro vs. basalt

Example Sentences

Bags of gabbro and similar calcium-bearing silicate rocks fill a shed out back and dot the office.

From The Wall Street Journal • Dec. 10, 2025

"These elements allowed us to look back through the chemical changes that TTG magmas go through and trace the melt compositions back to their initial state and source -- most likely a sort of gabbro."

From Science Daily • Jan. 31, 2024

Not getting a sample of this gabbro was frustrating, but scientists are already extracting valuable lessons from the momentary failure.

From Scientific American • Aug. 12, 2021

Pyroxenes are commonly found in mafic igneous rocks such as peridotite, basalt, and gabbro, as well as metamorphic rocks like eclogite and blue-schist.

From Textbooks • Jan. 1, 2017

The one exception is on Caribou Ridge, which is capped by a much altered gabbro.

From The Long Labrador Trail by Wallace, Dillon