Definition of acid in English:

acid

noun

  • 1A chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind.

    ‘rainwater is a very weak acid’
    Often contrasted with alkali or base
    ‘traces of acid’
    • ‘Most of the corrosive acid quickly evaporated from the road that was warmed by early morning sunshine and a fresh breeze helped it to quickly dissipate into the atmosphere.’
    • ‘It can withstand high temperatures and is resistant to many corrosive substances such as acids and alkalis.’
    • ‘Lactate, your body's buffering agent, neutralizes the acid that builds up in your legs and makes them burn during heavy exertion.’
    • ‘Saliva neutralizes acids that can cause tooth decay, but its production is greatly reduced during sleep.’
    • ‘I reach down and pry the knife she was holding out of her hands; it's a standard chainsteel model, but with a hollow edge filled with corrosive hexavalent acid.’
    • ‘Their roots will penetrate cracks in the rock and produce an organic acid that dissolves calcium carbonate.’
    • ‘Additionally, carbon dioxide and organic acids may be added to the water from the soil, where they form by decay of organic matter.’
    • ‘Copper is a moderately reactive metal that dissolves in most acids and alkalis.’
    • ‘Zinc is a fairly active metal that dissolves in both acids and strong alkalis.’
    • ‘It combines with most non-metals at high temperatures and reacts with both acids and alkalis.’
    • ‘These same sensors also prevent further stomach contents from entering the duodenum until the stomach acid is neutralized and diluted.’
    • ‘The creek began running the color of old blood, poisoned by acids and heavy metals leached from the coal mines.’
    • ‘A typical trick was to coat a gold object with a metal that could be dissolved by an acid.’
    • ‘The element is not very reactive chemically, although it does dissolve in most acids.’
    • ‘It also dissolves in most acids and reacts slowly with water to form compounds that tend to be yellowish or green in color.’
    • ‘The rotting process releases acids which dissolve metals into liquids which leach out of waste dumps and can poison local rivers.’
    • ‘Railroad crews also were checking the rail lines and a rail car was being sent along the route with a solution of baking soda and water to neutralize the acid.’
    • ‘Concentrated acids and caustic alkalis should be handled with the greatest care.’
    • ‘Two teenagers were lucky to still have their sight, after they were sprayed in the face with a corrosive acid in an apparently unprovoked attack on Chiswick High Road.’
    • ‘Strong acids are corrosive and this one is no exception; the stomach lining must be constantly renewed as it is eaten away.’
    1. 1.1 Bitter or cutting remarks or tone of voice.
      ‘she was unable to quell the acid in her voice’
      • ‘I guess I hadn't spoken with such acid in my tone for a while.’
      • ‘The bitterness and acid in his voice reassured me Peter was still in there, but he was very, very upset.’
      • ‘The acid of Mrs Shrewsbury's scorn reached a raw nerve as she pronounced: ‘Men - savages!’’
      • ‘‘Big surprise there,’ Jordan quipped, though with considerably less acid in his voice.’
      • ‘Her tone lacked its previous acid; she almost sounded sincere.’
      sarcasm, sardonicism, dryness, causticity, sharpness, acerbity, acid, bitterness, trenchancy, mordancy, cynicism
      View synonyms
  • 2Chemistry
    A molecule or other entity that can donate a proton or accept an electron pair in reactions.

    • ‘They would like to use their carborane acids to bind protons to atoms of the inert gas xenon.’
    • ‘The acid's active ingredient is positively charged hydrogen, so a transfer of electrons takes place between the zinc and the acid.’
    • ‘Weak acids have dissociable protons like strong acids, but they simply do not dissociate completely.’
    • ‘Several years ago, it appeared that the only solid acids that could support high proton transport were those based on sulfates or selenates.’
    • ‘These extra acid molecules are thought to make polyanaline dissolve in water because they are available to interact with water molecules in the liquid the plastic is bathed in.’
  • 3informal The drug LSD.

    • ‘Flashbacks can occur at any time after taking acid, sometimes even after many years.’
    • ‘He has used mescaline, cocaine and acid, although he has not indulged in intravenous drugs.’
    • ‘He looked around more, seeing many different things that he would never expect: cocaine, meth and acid.’
    • ‘Listening to this in the middle of the night is what I'd imagine having a particularly strange trip on acid would be like.’
    • ‘That heroin and acid were and are illegal didn't seem to stop him.’

adjective

  • 1Containing acid or having the properties of an acid; in particular, having a pH of less than 7.

    ‘poor, acid soils’
    Often contrasted with alkaline or basic
    • ‘Kochian's lab is also working on finding ways to grow crops on marginal lands such as acid soils, where toxic levels of aluminum limit crop production.’
    • ‘Carrot plants do not grow well in strongly acid soils; therefore, a pH range of 6.0 to 6.8 should be maintained for best results.’
    • ‘A specialist plant which prefers soil on the acid side but in pots use a good quality potting mix for Australian natives.’
    • ‘In the case of acid soils, burning decreases acidity, which starts to increase again during the planting period.’
    • ‘The entrance is enhanced by plants such as ready grown, trees, magnolias and other plants suited to the acid soil of the area with ready grown creepers lining the pillars.’
    • ‘In the garden it likes sun or partial shade and well-drained acid soil - like most Ericas it dislikes being grown in limy conditions.’
    • ‘If shrubs or trees are native to an area with acid soil and you're growing them in alkaline dirt, sure enough they'll probably become bug infested.’
    • ‘Boxwood prefer slightly acid to slightly alkaline soil and do very well when planted in early fall.’
    • ‘Mossy lawns that indicate acid soil may be dressed in late November with powdered chalk or lime at a rate of 8oz per sq yard.’
    • ‘The blunt truth is that the wet acid soils of the Highlands could not support any tolerable standard of living, particularly as the inhabitants could now compare their condition with those in other areas.’
    • ‘Preziosa has small mophead flowers that are usually a mix of pink, white and red that never get very blue even on acid soils and that turn crimson in autumn.’
    • ‘It used to be that, if you had a very acid soil, the hydrangeas would be bluer; more alkaline soil, your hydrangeas would be pinker.’
    • ‘So where better to focus than France's Loire Valley, known best for its grapes which thrive on acid soils and produce some of the best and most palatable wines to suit barbecue steaks or fish and seafood.’
    • ‘Space them about 6 feet apart in well-drained, slightly acid soil.’
    • ‘Unlike many magnolias, M. stellata will grow just as well on alkaline soils as it will on acid soil.’
    • ‘Azaleas and rhododendrons must have an acid soil.’
    • ‘They need well-drained acid soil and sun or partial shade and are best pruned in March.’
    • ‘Sorrel likes rich, moist, acid soil and will even grow in containers.’
    • ‘If you have an acid soil, a good way to rectify the situation is to rake lime into the ground in late winter.’
    • ‘Corn is less sensitive than legumes to acid soils.’
    caustic, corroding, eroding, erosive, abrasive, biting, mordant, burning, stinging
    View synonyms
  • 2Sharp-tasting or sour.

    ‘acid fruit’
    • ‘It is an acid cherry that provides a bittersweet flavour when fully ripe.’
    • ‘The mild fruit with a sweet and acid taste can get rid of wetness inside, enrich the body's energy and relieve internal heat.’
    • ‘Sour and acid tastes are liked, and are manifest in the use of lime juice, tamarind, etc.’
    • ‘It is medium bodied with surprisingly strong flavors, a crisp acid balance and a slightly bitter finish.’
    • ‘Balsamic vinegar is acid because it's vinegar after all, but when combined with fruits it seems to make a background flavor that enhances natural sweetness of the fruits.’
    • ‘I smiled as sweetly as I could and kissed her cheek as I breathed in the pungent acid aroma.’
    • ‘The taste is mildly acid and always astringent, sometimes very strongly so.’
    • ‘You can't eat it fresh because it's so acid, but often these highly acid fruits have the best flavour, and it makes the most wonderful fruit drinks, sorbets, ice creams and other things.’
    • ‘On the visit to the GP I saw a locum who said I must sit about for the next week, not use the computer, and keep off acid fruits.’
    • ‘They rely on a judicious ratio of noodle, meat and/or vegetables to broth and a sophisticated interplay of flavours which might include salty, sour, acid, sweet and spicy - hot.’
    • ‘This may enhance pleasant tastes and decrease salty, bitter, or acid tastes.’
    acidic, sour, tart, bitter, unsweetened, sharp, biting, acrid, pungent, acerbic, vinegary, vinegarish, acetic, acetous
    View synonyms
    1. 2.1 (of a person's remarks or tone) bitter or cutting.
      • ‘He has become more prominent since Henry took over in November 1999 and adds the sugar to the coach's acid remarks when things are not going well.’
      • ‘These cases attract great attention, and acid comments from magistrates.’
      • ‘Her interpretation is perfectly pitched to Catherine's acid sarcasm.’
      • ‘The intention here is surely to eliminate ‘producer opera’, about which Sharpe makes some acid remarks.’
      • ‘Nevertheless, one writer of independent means abstained from all public pronouncements and confined himself to acid criticisms of the government in his private diary.’
      • ‘‘Please leave, I do not wish to speak to you,’ she said in quietly acid tones that immediately raised his concern.’
      • ‘Luigi Dallapiccola's acid remark about Vivaldi, often repeated, is misleading.’
      • ‘Fired by anger and fear, I spun to face my assailant, acid demands on my lips - and the words died.’
      • ‘Northam's acid comments aside, however, Stoppard falls short of his Shakespeare In Love triumph, while John Barry's soundtrack merely ticks over.’
      • ‘The letter ends with more acid advice: Since the politician has a lifetime pension, he'd be better off polishing his golf game.’
      • ‘Asked what he thinks about that constant speculation, the Frenchman's acid response is that his counterpart must have a good agent.’
      • ‘One final matter is worth mentioning, and this is the acid comments about folklore and folklorists in Alice's diaries.’
      • ‘Sadie spat in an acid tone, refusing to even acknowledge that the woman was her mother.’
      • ‘His antimilitarism and acid comments on ‘the military mind’ will probably antagonize many present-day soldiers.’
      • ‘William looked down in horror as he tried to keep composure, but the very fear of what his acid remarks could do to this man's mood made him gulp and shift once in his feet.’
      • ‘As he took a moment to rest, dropping her feet to the ground but keeping a firm grip on the ruffled sleeve of her shirt, he received an acid remark.’
      • ‘Sometimes he brings his wife, to swap acid comments with the bartender.’
      • ‘She is dressed in a body-hugging, full-length stripper gown and armed with an acid retort for every smart-aleck remark.’
      • ‘He makes some quite acid comments about the seventies mystical counterculture which make for very amusing reading now.’
      • ‘Ignoring her acid tone, he mumbled, ‘You're very snappy this afternoon.’’
      acerbic, sarcastic, sharp, sardonic, satirical, scathing, cutting, razor-edged
      View synonyms
    2. 2.2 (of a color) intense or bright.
      ‘an acid green’
      • ‘Using deft brushwork and a palette of acid greens, vibrant pinks and neon blues, Christine Major presents a series of seductive paintings of animals at the Montreal Museum of Fine Arts.’
      • ‘Throughout, Gozi used muted shades of charcoal-blue and bottle-green with splashes of bright apple, turquoise and acid pink.’
      • ‘Dark green, ocean blue, metallic greys and whites, black and vibrant flashes of cobalt blue and acid yellow are the season's colours.’
      • ‘She reckons you can get away with virtually anything, particularly acid colours.’
      • ‘Those eyes had undergone a change from murky grunge to acid green as he repeated his question with more ferocity.’
      • ‘Anita Dongre presented her pastel collection of chikan work for the Spring-Summer 2001 season in pastel shades of pink, acid green and turquoise blue.’
      • ‘Then her eyes started to glow an acid green colour that swirled in her eyes, almost manically. ‘Sweet dreams.’’
      • ‘My designs are usually quite dark, but this time the palette has acid greens and pinks.’
      • ‘In acid bright livery, these compact vans are the latest word in funky design.’
      • ‘The art students brought their acid colour combinations, their lilacs, tangerines and lime greens from abstract painting.’
      • ‘She wore an acid green skating dress made by her mother.’
      • ‘The tonal approach of Twin Garden is based on a range of greens from forest to acid backed up by a similar variety of pinks and purples.’
      • ‘White was combined with a rainbow of colours including lilac, baby pink, lemon, acid green and turquoise candy stripes.’
      • ‘I see all these colours against a background of acid yellow, with a touch of green for envy, malice and general discontent.’
      • ‘The sky was a dark grey colour, occasionally coloured with deep red and acid green.’
      • ‘But the real innovation is the fact that you can change the background colour from that acid green to any combination of two intense primary colours.’
      • ‘In a Dolce and Gabanna dress and acid green Philip Treacy hat, antique dealer Sarah Vernon, 38, drew approving glances from fellow-racegoers.’
      • ‘Allfree's bold use of colour - citron, turquoise, acid green, crimson - breathes new life into the building.’
      • ‘He was tall, about six foot two, with dark hair and acid green eyes.’
      • ‘From the cool modernity of the main space, the bedrooms and bathroom offer a contradictory riot of colour, walls varying from acid green to purple throughout the five bedrooms and bathrooms.’
  • 3Geology
    (of rock, especially lava) containing a relatively high proportion of silica.

    • ‘Acraman occurs in the Gawler Range Volcanics, a Mesoproterozoic continental suite of mainly acid lavas and ash flows.’
    • ‘The Haluut Bulag melange contains lenses of limestone, sandstone, chert, tuff, minor acid volcanic material, and vesicular basalt.’
    • ‘These deposits are intimately associated with the porphyric parts of intermediate to acid plutons in orogenic belts.’
    • ‘In the Southern Central Iberian Zone there are minor acid volcanic rocks intercalated with Caradoc-Ashgill limestones.’
    • ‘At higher elevations on these mountains, the parent material is acid crystalline rock.’
    1. 3.1Metallurgy Relating to or denoting steelmaking processes involving silica-rich refractories and slags.
      • ‘As it happened, Workington's adherence to acid steelmaking sealed the fate of the ore dock in the next few years.’
      • ‘The wetting agents typically used in the acid process are relatively rinse- free when compared to alkaline systems.’
      • ‘In the acid processes, deoxidation can take place in the furnaces, leaving a reasonable time for the inclusions to rise into the slag and so be removed before casting.’
      • ‘Therefore, a business opportunity could be created for an entrepreneur interested in running the acid separation and purification process.’
      • ‘Ideally, a non-contact sensor would be inserted into the acid process in an appropriate location and allowed to communicate with a base instrument located remotely in the safe environment of a control room.’

Origin

Early 17th century (in the sense sour-tasting): from Latin acidus, from acere be sour.

Pronunciation

acid

/ˈasəd/