caustic
Americanadjective
noun
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a caustic substance.
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Optics.
adjective
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capable of burning or corroding by chemical action
caustic soda
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sarcastic; cutting
a caustic reply
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of, relating to, or denoting light that is reflected or refracted by a curved surface
noun
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Also called: caustic surface. a surface that envelops the light rays reflected or refracted by a curved surface
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Also called: caustic curve. a curve formed by the intersection of a caustic surface with a plane
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chem a caustic substance, esp an alkali
Other Word Forms
- caustical adjective
- caustically adverb
- causticity noun
- causticly adverb
- causticness noun
- noncaustic adjective
- noncaustically adverb
- overcaustic adjective
- overcaustically adverb
- overcausticity noun
- uncaustic adjective
- uncaustically adverb
Etymology
Origin of caustic
1350–1400; Middle English < Latin causticus < Greek kaustikós burning, caustic, equivalent to kaust ( ós ) burnt (verbal adjective of kaíein to burn) + -ikos -ic
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Lyrical saint Nick Cave was more caustic — notoriously so — when he shared how he felt about these boys of California’s endless summer.
From Salon • Apr. 4, 2026
At this point, you just don’t like each other, which makes communication feel even more caustic.
From MarketWatch • Feb. 27, 2026
The federal investigators encountered puddles of crude oil on the facility grounds, as well as caustic fumes emanating from the facility, resulting in violations for air quality and other environmental infractions.
From Los Angeles Times • Feb. 14, 2026
Around him orbits a constellation of classmates - caustic, thoughtful, restless - who debate Swiss-French architect Le Corbusier, Karl Marx and the price of cigarettes with equal seriousness.
From BBC • Feb. 13, 2026
Gregarious by nature, Hall proved to be a skillful raconteur with a caustic Kiwi wit.
From "Into Thin Air" by Jon Krakauer
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
