• synonyms


  1. the dioxide form of silicon, SiO2, occurring especially as quartz sand, flint, and agate: used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.
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Origin of silica

1795–1805; < New Latin, derivative of Latin silex silex
Also called silicon dioxide.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for silica

Historical Examples of silica

  • It is composed of silica, alumina, carbonate of lime, magnesia and oxide of iron.

    Museum of Antiquity

    L. W. Yaggy

  • The most important determinations for these are total alkali and silica.

  • Many of these knives have silica blades, some of the handles being of jade.

  • Silica is soluble in alkaline waters, especially when these are hot.

    The Elements of Geology

    William Harmon Norton

  • Hence the relationship of the oxygen in the base to the oxygen in the silica is as one to two.

    The Potter's Craft

    Charles F. Binns

British Dictionary definitions for silica


  1. the dioxide of silicon, occurring naturally as quartz, cristobalite, and tridymite. It is a refractory insoluble material used in the manufacture of glass, ceramics, and abrasives
  2. short for silica glass
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Word Origin for silica

C19: New Latin, from Latin: silex
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 silica


"hard silicon dioxide," 1801, Modern Latin, from Latin silex (genitive silicis) "flint, pebble," on model of alumina, soda.

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Online Etymology Dictionary, © 2010 Douglas Harper

silica in Medicine


  1. A crystalline compound occurring abundantly as quartz, sand, and many other minerals and used to manufacture a variety of materials, especially glass and concrete.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

silica in Science


  1. A chemical compound that is the main constituent of most of the Earth's rocks. Silica occurs naturally in five crystalline forms (quartz, tridymite, cristobalite, coesite, and stishovite), in a cryptocrystalline form (chalcedony), and in an amorphous form (opal). It is also the main chemical compound in sand. Silica is used to make glass, concrete, and other materials. Also called silicon dioxide. Chemical formula: SiO2.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.