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
    [mass noun] ‘traces of acid’
    • ‘It can withstand high temperatures and is resistant to many corrosive substances such as acids and alkalis.’
    • ‘Saliva neutralizes acids that can cause tooth decay, but its production is greatly reduced during sleep.’
    • ‘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.’
    • ‘The creek began running the color of old blood, poisoned by acids and heavy metals leached from the coal mines.’
    • ‘Zinc is a fairly active metal that dissolves in both acids and strong alkalis.’
    • ‘Lactate, your body's buffering agent, neutralizes the acid that builds up in your legs and makes them burn during heavy exertion.’
    • ‘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.’
    • ‘It combines with most non-metals at high temperatures and reacts with both acids and alkalis.’
    • ‘The element is not very reactive chemically, although it does dissolve in most acids.’
    • ‘Additionally, carbon dioxide and organic acids may be added to the water from the soil, where they form by decay of organic matter.’
    • ‘A typical trick was to coat a gold object with a metal that could be dissolved by an acid.’
    • ‘It also dissolves in most acids and reacts slowly with water to form compounds that tend to be yellowish or green in color.’
    • ‘Concentrated acids and caustic alkalis should be handled with the greatest care.’
    • ‘Copper is a moderately reactive metal that dissolves in most acids and alkalis.’
    • ‘Strong acids are corrosive and this one is no exception; the stomach lining must be constantly renewed as it is eaten away.’
    • ‘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.’
    • ‘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.’
    • ‘These same sensors also prevent further stomach contents from entering the duodenum until the stomach acid is neutralized and diluted.’
    • ‘The rotting process releases acids which dissolve metals into liquids which leach out of waste dumps and can poison local rivers.’
    1. 1.1Bitter or cutting remarks or tone of voice.
      ‘she was unable to quell the acid in her voice’
      • ‘Her tone lacked its previous acid; she almost sounded sincere.’
      • ‘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!’’
      • ‘I guess I hadn't spoken with such acid in my tone for a while.’
      • ‘‘Big surprise there,’ Jordan quipped, though with considerably less acid in his voice.’
  • 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.’
    • ‘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.’
    • ‘Several years ago, it appeared that the only solid acids that could support high proton transport were those based on sulfates or selenates.’
    • ‘Weak acids have dissociable protons like strong acids, but they simply do not dissociate completely.’
  • 3informal The drug LSD.

    • ‘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.’
    • ‘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.’
    • ‘Flashbacks can occur at any time after taking acid, sometimes even after many years.’

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
    • ‘In the case of acid soils, burning decreases acidity, which starts to increase again during the planting period.’
    • ‘Corn is less sensitive than legumes to acid soils.’
    • ‘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.’
    • ‘If you have an acid soil, a good way to rectify the situation is to rake lime into the ground in late winter.’
    • ‘Unlike many magnolias, M. stellata will grow just as well on alkaline soils as it will on acid soil.’
    • ‘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.’
    • ‘They need well-drained acid soil and sun or partial shade and are best pruned in March.’
    • ‘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.’
    • ‘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.’
    • ‘Sorrel likes rich, moist, acid soil and will even grow in containers.’
    • ‘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.’
    • ‘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.’
    • ‘A specialist plant which prefers soil on the acid side but in pots use a good quality potting mix for Australian natives.’
    • ‘In the garden it likes sun or partial shade and well-drained acid soil - like most Ericas it dislikes being grown in limy conditions.’
    • ‘Space them about 6 feet apart in well-drained, slightly acid soil.’
    • ‘Boxwood prefer slightly acid to slightly alkaline soil and do very well when planted in early fall.’
    • ‘Azaleas and rhododendrons must have an acid soil.’
    • ‘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.’
    • ‘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.’
    caustic, corroding, eroding, erosive, abrasive, biting, mordant, burning, stinging
    View synonyms
  • 2Sharp-tasting or sour.

    ‘acid fruit’
    • ‘The mild fruit with a sweet and acid taste can get rid of wetness inside, enrich the body's energy and relieve internal heat.’
    • ‘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.’
    • ‘It is medium bodied with surprisingly strong flavors, a crisp acid balance and a slightly bitter finish.’
    • ‘I smiled as sweetly as I could and kissed her cheek as I breathed in the pungent acid aroma.’
    • ‘This may enhance pleasant tastes and decrease salty, bitter, or acid tastes.’
    • ‘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.’
    • ‘Sour and acid tastes are liked, and are manifest in the use of lime juice, tamarind, etc.’
    • ‘The taste is mildly acid and always astringent, sometimes very strongly so.’
    • ‘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.’
    • ‘It is an acid cherry that provides a bittersweet flavour when fully ripe.’
    • ‘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.’
    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 makes some quite acid comments about the seventies mystical counterculture which make for very amusing reading now.’
      • ‘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.’
      • ‘Nevertheless, one writer of independent means abstained from all public pronouncements and confined himself to acid criticisms of the government in his private diary.’
      • ‘Fired by anger and fear, I spun to face my assailant, acid demands on my lips - and the words died.’
      • ‘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.’
      • ‘The intention here is surely to eliminate ‘producer opera’, about which Sharpe makes some acid remarks.’
      • ‘Ignoring her acid tone, he mumbled, ‘You're very snappy this afternoon.’’
      • ‘His antimilitarism and acid comments on ‘the military mind’ will probably antagonize many present-day soldiers.’
      • ‘Her interpretation is perfectly pitched to Catherine's acid sarcasm.’
      • ‘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.’
      • ‘The letter ends with more acid advice: Since the politician has a lifetime pension, he'd be better off polishing his golf game.’
      • ‘These cases attract great attention, and acid comments from magistrates.’
      • ‘Luigi Dallapiccola's acid remark about Vivaldi, often repeated, is misleading.’
      • ‘‘Please leave, I do not wish to speak to you,’ she said in quietly acid tones that immediately raised his concern.’
      • ‘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.’
      • ‘Northam's acid comments aside, however, Stoppard falls short of his Shakespeare In Love triumph, while John Barry's soundtrack merely ticks over.’
      • ‘She is dressed in a body-hugging, full-length stripper gown and armed with an acid retort for every smart-aleck remark.’
      • ‘Sometimes he brings his wife, to swap acid comments with the bartender.’
    2. 2.2(of a color) intense or bright.
      ‘an acid green’
      • ‘In a Dolce and Gabanna dress and acid green Philip Treacy hat, antique dealer Sarah Vernon, 38, drew approving glances from fellow-racegoers.’
      • ‘Throughout, Gozi used muted shades of charcoal-blue and bottle-green with splashes of bright apple, turquoise and acid pink.’
      • ‘My designs are usually quite dark, but this time the palette has acid greens and pinks.’
      • ‘Those eyes had undergone a change from murky grunge to acid green as he repeated his question with more ferocity.’
      • ‘In acid bright livery, these compact vans are the latest word in funky design.’
      • ‘She reckons you can get away with virtually anything, particularly acid colours.’
      • ‘The sky was a dark grey colour, occasionally coloured with deep red and acid green.’
      • ‘Dark green, ocean blue, metallic greys and whites, black and vibrant flashes of cobalt blue and acid yellow are the season's colours.’
      • ‘White was combined with a rainbow of colours including lilac, baby pink, lemon, acid green and turquoise candy stripes.’
      • ‘He was tall, about six foot two, with dark hair and acid green eyes.’
      • ‘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.’
      • ‘I see all these colours against a background of acid yellow, with a touch of green for envy, malice and general discontent.’
      • ‘The art students brought their acid colour combinations, their lilacs, tangerines and lime greens from abstract painting.’
      • ‘Then her eyes started to glow an acid green colour that swirled in her eyes, almost manically. ‘Sweet dreams.’’
      • ‘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.’
      • ‘She wore an acid green skating dress made by her mother.’
      • ‘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.’
      • ‘Allfree's bold use of colour - citron, turquoise, acid green, crimson - breathes new life into the building.’
      • ‘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.’
      • ‘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.’
  • 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.’
    • ‘At higher elevations on these mountains, the parent material is acid crystalline rock.’
    • ‘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.’
    1. 3.1Metallurgy
      Relating to or denoting steelmaking processes involving silica-rich refractories and slags.
      • ‘Therefore, a business opportunity could be created for an entrepreneur interested in running the acid separation and purification process.’
      • ‘As it happened, Workington's adherence to acid steelmaking sealed the fate of the ore dock in the next few years.’
      • ‘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.’
      • ‘The wetting agents typically used in the acid process are relatively rinse- free when compared to alkaline systems.’
      • ‘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/