sil·​i·​ca | \ ˈsi-li-kə How to pronounce silica (audio) \

Definition of silica

: the dioxide of silicon SiO2 occurring in crystalline, amorphous, and impure forms (as in quartz, opal, and sand respectively)

Examples of silica in a Sentence

Recent Examples on the Web

In 2010, Santa Anita became one of several prominent tracks to abandon synthetic racetracks made of sand, rubber and silica after a short-lived experiment. Corina Knoll, New York Times, "Why So Many Horses Have Died at Santa Anita," 26 June 2019 After the tree perished, water carrying silica and other minerals coated the log to preserve the wood and protect some of those organic components inside. Riley Black, Smithsonian, "A 16-Million-Year-Old Tree Tells a Deep Story of the Passage of Time," 10 June 2019 Common ingredients include stain removers (such as sodium tripolyphosphateor hexametaphosphate and hydrated silica) and bleach, often listed as calcium peroxide or hydrogen peroxide. Joanne Chen, Redbook, "Teeth: An Owner's Manual," 24 July 2017 According to the listing, the ingredients include a propellant, alcohol, iron oxides, talc, and fumed silica. Cheryl Wischhover, Vox, "How spray-on hair does (and doesn’t) work," 17 Dec. 2018 Polly Trottenberg, the city’s transportation commissioner and an MTA board member appointed by Mayor Bill de Blasio, raised concerns Tuesday about the silica dust that could accumulate during the demolition of concrete in the tunnel. Paul Berger, WSJ, "MTA Board Members Grill Consultants About Revised L Train Plan," 15 Jan. 2019 The silica and hydrogen peroxide in it strengthen nails, brighten hair and clear up acne and inflammation. Alexandra Tunell, Harper's BAZAAR, "The Biggest Korean Beauty Trends to Know for 2016," 15 Jan. 2016 With tons of basalt rock around, the chemistry of the water would have reflected that rock—high in iron, magnesium, and silica. Scott K. Johnson, Ars Technica, "The secret to Mars’ past warmth could be beneath Curiosity’s wheels," 9 Aug. 2018 Breathing in tiny silica particles has been linked to lung cancer, liver disease and an incurable swelling of the lungs. Garance Burke, The Seattle Times, "Tenants allege Kushner firm pushed them out of their homes," 17 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'silica.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of silica

circa 1801, in the meaning defined above

History and Etymology for silica

New Latin, from Latin silic-, silex hard stone, flint

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Statistics for silica

Last Updated

3 Jul 2019

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Time Traveler for silica

The first known use of silica was circa 1801

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English Language Learners Definition of silica

: a chemical that contains silicon, that is found in sand and quartz, and that is used to make glass


sil·​i·​ca | \ ˈsil-i-kə How to pronounce silica (audio) \

Medical Definition of silica

: the dioxide of silicon SiO2 that is used as an ingredient of simethicone and that occurs naturally in crystalline, amorphous, and impure forms (as in quartz, opal, and sand respectively)

called also silicon dioxide

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More from Merriam-Webster on silica

Spanish Central: Translation of silica

Nglish: Translation of silica for Spanish Speakers Encyclopedia article about silica

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