capable of burning, corroding, or destroying living tissue.
severely critical or sarcastic: a caustic remark.


a caustic substance.

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
Related formscaus·ti·cal·ly, caus·tic·ly, adverbcaus·tic·i·ty [kaw-stis-i-tee] /kɔˈstɪs ɪ ti/, caus·tic·ness, nounnon·caus·tic, adjectivenon·caus·ti·cal·ly, adverbo·ver·caus·tic, adjectiveo·ver·caus·ti·cal·ly, adverbo·ver·caus·tic·i·ty, nounun·caus·tic, adjectiveun·caus·ti·cal·ly, adverb

Synonyms for caustic Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for caustic

Contemporary Examples of caustic

Historical Examples of caustic

British Dictionary definitions for caustic



capable of burning or corroding by chemical actioncaustic soda
sarcastic; cuttinga caustic reply
of, relating to, or denoting light that is reflected or refracted by a curved surface


Also called: caustic surface a surface that envelops the light rays reflected or refracted by a curved surface
Also called: caustic curve a curve formed by the intersection of a caustic surface with a plane
chem a caustic substance, esp an alkali
Derived Formscaustical, adjectivecaustically, adverbcausticity (kɔːˈstɪsɪtɪ) or causticness, noun

Word Origin for caustic

C14: from Latin causticus, from Greek kaustikos, from kaiein to burn
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 caustic

c.1400, "burning, corrosive," from Latin causticus "burning, caustic," from Greek kaustikos "capable of burning; corrosive," from kaustos "combustible; burnt," verbal adjective from kaiein, the Greek word for "to burn" (transitive and intransitive) in all periods, of uncertain origin with no certain cognates outside Greek. Figurative sense of "sarcastic" is attested from 1771. As a noun, early 15c., from the adjective.

Online Etymology Dictionary, © 2010 Douglas Harper

caustic in Medicine




A hydroxide of a light metal.
A caustic material or substance.


Capable of burning, corroding, dissolving, or eating away by chemical action.
Of or relating to light emitted from a point source and reflected or refracted from a curved surface.
Causing a burning or stinging sensation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.