Definition of caustic in English:



  • 1Able to burn or corrode organic tissue by chemical action.

    ‘a caustic cleaner’
    • ‘Regeneration of this resin is by a caustic brine solution.’
    • ‘Therefore, be very careful to keep caustic chemicals away from skin and eyes and wear protective clothing.’
    • ‘Initially firefighters used hand-held jets to tackle the blaze while experts established that four different chemicals were involved that were caustic and could cause burns.’
    • ‘Some of the chemicals - including caustic hydrogen fluoride and deadly arsine gas - are toxic, and the fossil fuel consumed contributes to global warming, says Williams.’
    • ‘The list includes sodium hydroxide and potassium hydroxide, caustic chemicals that will rip the skin off your fingers and the lining from the throat.’
    • ‘It is also the opposite of baking and washing soda; it is acidic and therefore neutralizes alkaline or caustic substances.’
    • ‘Concentrated acids and caustic alkalis should be handled with the greatest care.’
    • ‘Others may contain noxious or caustic materials that could burn the mucous membranes of the mouth.’
    • ‘It may be worth noting that because caustic chemicals are used in hair dyes, perms, and relaxers, you would be wise to place your hair in the hands of a professional.’
    • ‘The caustic burn was treated successfully, and the patient eventually achieved good vision after uncomplicated cataract surgery.’
    • ‘Alkaline substances did not have a sour taste but were caustic and felt slippery.’
    • ‘Lye is hazardous, very caustic, and will burn skin.’
    • ‘Never use caustic household chemicals to clean your leather items.’
    • ‘Now you can use anti-freeze or salts to lower the melting point, but you can only go so far with that and still allow life to exist, otherwise the chemicals become too caustic.’
    • ‘Because alkaline strippers are so caustic, great care must also be taken during their application.’
    • ‘It is done at high temperatures with caustic chemicals in factory conditions.’
    • ‘This pollutant can be absorbed by both your lungs and your skin and result in caustic burns, kidney and liver damage and hyperactivity.’
    • ‘The process is relatively simple, although the chemicals required are caustic and need to be handled carefully.’
    • ‘When these materials burn, they release dense smoke and toxic fumes, such as hydrogen cyanide and carbon monoxide, which are caustic to skin and eyes and can be lethal if inhaled.’
    • ‘Sodium hydroxide is a caustic type of chemical that actually softens hair fibers.’
    corrosive, corroding, mordant, acid, alkaline, burning, stinging, acrid, harsh, destructive
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  • 2Sarcastic in a scathing and bitter way.

    ‘the players were making caustic comments about the refereeing’
    • ‘One of the most caustic comments on the present-day globalisation has come from Robert Samuelson in the Newsweek of February 24.’
    • ‘It's more irreverent, sarcastic, and caustic than what I'm used to hearing from Army officer wives I knew - and female Army officers in dual-military couples.’
    • ‘I am continually surprised by Sharon's creativity even if it is currently directed towards caustic but witty sarcasm.’
    • ‘When they pulled out of NATO 40 years ago Secretary of State Dean Rusk had a bitterly caustic response.’
    • ‘He had been a serious, shy young man whose wit showed only in the bitterly caustic cartoon strips he drew, the strips that were rejected by paper after paper.’
    • ‘Joel had to bite back the caustic remark that burned on the tip of his tongue.’
    • ‘The show is a delightful, gin-soaked celebration of the work of Dorothy Parker, legendary American critic, columnist and queen of caustic wit.’
    • ‘He'd left that after an hour of wandering around, trying not to sound too caustic in his comments about the whole thing.’
    • ‘He is equally caustic about Western art historians and critics.’
    • ‘This awareness lends even the most caustic social commentary additional gravity, or sadness.’
    • ‘She's really quite funny, in a bitter, caustic kind of way.’
    • ‘She was a caustic critic of charismatic ministers who speechify but don't mobilize.’
    • ‘Her caustic, waspish comments on the other housemates were biting and bitchy, but always spot on.’
    • ‘She was attacked in 1930 by the caustic critic Wyndham Lewis for her ‘fashionable dimness‘.’
    • ‘As Ireland missed three times from the penalty spot and Spain took advantage, the first caustic comment on the team's performance came from former local soccer star Tom Lambert.’
    • ‘Revered by many of today's generation of poets, Stephens was generally considered a spoken word pioneer, not to mention an often caustic literary critic for the Mirror.’
    • ‘Throughout the trial he evinced a range of carefully calibrated emotions - caustic, sarcastic, disbelieving and, at this moment, outraged.’
    • ‘She's been compared to Eminem for caustic wordplay that would sound awesome atop some straight hip-hop, but that would be too easy.’
    • ‘In 1890 he published The Gentle Art of Making Enemies, a collection of caustic letters and comment.’
    • ‘The pattern of caustic complaints and sarcastic responses slowly gave way to a new pattern of care toward one another.’
    sarcastic, cutting, biting, mordant, stinging, sharp, bitter, scathing, derisive, sardonic, ironic, scornful, trenchant, acerbic, vitriolic, tart, acid, pungent, acrimonious, astringent, rapier-like, razor-edged, critical, polemic, virulent, venomous, waspish
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  • 3Physics
    Formed by the intersection of reflected or refracted parallel rays from a curved surface.

    • ‘He also investigated caustic curves and in particular he studied these associated curves of the parabola, the logarithmic spiral and epicycloids around 1692.’
    • ‘For example they worked together on caustic curves during 1692-93 although they did not publish the work jointly.’
    • ‘The lower right has a metal ring with a caustic reflection.’
    • ‘In On burning mirrors Diocles also studies the problem of finding a mirror such that the envelope of reflected rays is a given caustic curve or of finding a mirror such that the focus traces a given curve as the Sun moves across the sky.’
    • ‘Sturm's theoretical work in mathematical physics involved the study of caustic curves, and poles and polars of conic sections.’


  • 1A caustic substance.

    • ‘Production is potentially dangerous, as you need to heat volatile methanol with caustics.’
    • ‘Aughinish jetty receives ore, oil and caustic and exports the finished aluminium oxide.’
    • ‘Spent grain, yeast, ethanol, and acids and caustics used for cleaning are all sent out to be used for feed for cattle or reprocessed and reused industrially.’
    • ‘Loam and caustic might be thought of as the conditions of existence: the one an especially fertile soil, life-giving; the other a burning substance that destroys living tissue.’
    • ‘The scenes below show caustics, which are very difficult to render.’
  • 2Physics
    A caustic surface or curve.

    • ‘The caustic of the tricuspoid, where the rays are parallel and in any direction, is an astroid.’
    • ‘Nevertheless, this elucidation of the generic discontinuous change has shed light upon many optical phenomena where caustics and diffraction occur.’
    • ‘However with ray tracing, shadow mapping, radiosity, and caustics, an algorithm to compute light reflected from curved or transparent surfaces, it is easy to create multi-layered soft lights and shadows in LightWave.’
    • ‘The caustic of the equiangular spiral, where the pole is taken as the radiant, is an equal equiangular spiral.’
    • ‘The caustic of a circle with radiant point on the circumference is a cardioid, while if the rays are parallel then the caustic is a nephroid.’


Late Middle English: via Latin from Greek kaustikos, from kaustos ‘combustible’, from kaiein ‘to burn’.