[buh-sawlt, bas-awlt, bey-sawlt]
See more synonyms for basalt on
  1. the dark, dense igneous rock of a lava flow or minor intrusion, composed essentially of labradorite and pyroxene and often displaying a columnar structure.

Origin of basalt

1595–1605; < Latin basaltēs, a misreading, in manuscripts of Pliny, of basanītēs < Greek basanī́tēs (líthos) touchstone, equivalent to básan(os) touchstone (ultimately < Egyptian bh̬n(w) graywacke) + -ītēs -ite1
Related formsba·sal·tic, ba·sal·tine [buh-sawl-tin, -tahyn] /bəˈsɔl tɪn, -taɪn/, adjectivesub·ba·sal·tic, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for basalt

slag, magma, basalt, ashes, scoria, obsidian, coulee

Examples from the Web for basalt

Contemporary Examples of basalt

Historical Examples of basalt

  • Many varieties of stone were used, but the preference was given to basalt.

    The Railroad Question

    William Larrabee

  • Behold, my flesh is solid as basalt, my bones are bars of steel!

    The Mummy's Foot

    Thophile Gautier

  • The statues of basalt rolled their eyes and smiled hideously.

    King Candaules

    Thophile Gautier

  • A good solid rock, like basalt, can be cut into slices of about 3/32 inch thick.

    On Laboratory Arts

    Richard Threlfall

  • Of what use would porphyry, or granite, or basalt be for such purposes?

    Pagan and Christian Rome

    Rodolfo Lanciani

British Dictionary definitions for basalt


  1. a fine-grained dark basic igneous rock consisting of plagioclase feldspar, a pyroxene, and olivine: the most common volcanic rock and usually extrusiveSee flood basalt
  2. a form of black unglazed pottery resembling basalt
Derived Formsbasaltic, adjective

Word Origin for basalt

C18: from Late Latin basaltēs, variant of basanītēs, from Greek basanitēs touchstone, from basanos, of Egyptian origin
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 basalt

c.1600, from Late Latin basaltes, misspelling of Latin basanites "very hard stone," from Greek basanites "a species of slate used to test gold," from basanos "touchstone." Not connected with salt. Said by Pliny ["Historia," 36.58] to be an African word, perhaps Egyptian bauhan "slate." Any hard, very dark rock would do as a touchstone; the assayer compared the streak left by the alleged gold with that of real gold or baser metals. Hence Greek basanizein "to be put to the test, examined closely, cross-examined, to be put to torture."

Online Etymology Dictionary, © 2010 Douglas Harper

basalt in Science


[bə-sôlt, bāsôlt′]
  1. A dark, fine-grained, igneous rock consisting mostly of plagioclase feldspar and pyroxene, and sometimes olivine. Basalt makes up most of the ocean floor and is the most common type of lava. It sometimes cools into characteristic hexagonal columns, as in the Giant's Causeway in Anterim, Northern Island. It is the fine-grained equivalent of gabbro.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

basalt in Culture


[(buh-sawlt, bay-sawlt)]

A hard, dense igneous rock that makes up much of the material in tectonic plates. The part of the Earth's crust beneath the oceans consists mainly of basalt whereas continental crust consists mainly of less dense rocks, such as granite. (See plate tectonics.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.