basalt

noun

ba·​salt bə-ˈsȯlt How to pronounce basalt (audio) ˈbā-ˌsȯlt How to pronounce basalt (audio)
: a dark gray to black dense to fine-grained igneous rock that consists of basic plagioclase, augite, and usually magnetite
basaltic
bə-ˈsȯl-tik How to pronounce basalt (audio)
adjective

Examples of basalt in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Travelers who’d rather be outside should drive south on Snake River Road to Buffalo Eddy, where hundreds of petroglyphs etched into the basalt by Nez Perce ancestors thousands of years ago remain visible from the riverbank. — Lauren Mowery, Forbes.com, 29 July 2026 The structure leans heavily on concrete, steel and glass, but it’s warmed by wood, basalt and marble finishes and by the way the house frames the surrounding terrain. — David Caraccio, Sacbee.com, 25 July 2026 Giant's Causeway The Giant's Causeway in Northern Ireland offers a spectacular foreground for the eclipse, with the sun appearing low above the Atlantic beyond the famous basalt columns. — Jamie Carter, Space.com, 15 July 2026 The 1500 feet-long sculpture, made of 6000 tons of black basalt rock and earth, juts out of the basin and is encrusted with white salt, having been altered over the years by the salty pink water that used to flow there. — Lara Johnson-Wheeler, Vogue, 3 July 2026 See All Example Sentences for basalt

Word History

Etymology

Latin basaltes, manuscript variant of basanites touchstone, from Greek basanitēs (lithos), from basanos touchstone, from Egyptian bḫnw

First Known Use

1601, in the meaning defined above

Time Traveler
The first known use of basalt was in 1601

Rhymes for basalt

See All Rhymes for basalt

Browse Nearby Words

basal rot
basalt
basalt dome
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Cite this Entry

“Basalt.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/basalt. Accessed 5 Aug. 2026.

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Kids Definition

basalt

noun
ba·​salt bə-ˈsȯlt How to pronounce basalt (audio) ˈbā-ˌsȯlt How to pronounce basalt (audio)
: a dark gray to black usually fine-grained igneous rock
basaltic
bə-ˈsȯl-tik How to pronounce basalt (audio)
adjective

More from Merriam-Webster on basalt

Nglish: Translation of basalt for Spanish Speakers

Britannica.com: Encyclopedia article about basalt

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