acid

Pluralacids

Formsacider, acidest

1. 1
   nouncountable or uncountable

   A corrosive substance capable of burning or dissolving the materials it contacts.

   The spilled acid corroded the lab bench within minutes.

   Strong acids can dissolve certain metals entirely.

2. 2
   nouncountable or uncountable

   A substance characterized by a sour taste.

   Cooks often add an acid such as lemon juice to balance a rich dish.

   The acid in unripe fruit makes your mouth pucker.

3. 3
   nounslanguncountable

   LSD; a hallucinogenic drug that produces altered perception and vivid sensory distortions.

   The band's early shows were fueled by acid and waves of feedback.

   She took acid once in college and never tried it again.

   SimilarLSD

   Note

   The name is counterculture shorthand, cut down from the drug's full chemical name, lysergic acid diethylamide. It is a mass noun: you take acid, not an acid. Its signature idiom is drop acid, which Joe David Brown's The Hippies (1967) explains for outsiders as to ingest LSD. Away from slang settings, LSD is the neutral, safer term.

4. 4
   nouncountable or uncountable

   In chemistry, a compound that releases hydrogen ions, or protons, when it dissolves in water, as defined by Arrhenius.

   Hydrochloric acid releases hydrogen ions the moment it dissolves.

   Chemists classify a proton-yielding compound as an acid in water.

   Oppositebase, alkali

   Note

   Chemistry has three acid definitions, and this is the narrowest. It is tied to water: a compound counts as an Arrhenius acid only when it dissolves and releases hydrogen ions. The broader frameworks, the proton-donor definition and the electron-pair definition, carry the idea beyond water. As a count noun it names individual compounds, often in the plural after a run of qualifiers, as in gibberellic and abscisic acids.

5. 5
   adjective

   Sour, sharp, or biting to the taste; tart, with the tang of vinegar.

   The sauce turned unpleasantly acid after too much lemon juice.

   He detected an acid edge in the unripe apple.

   Similarsour, tart, sharp, vinegary, tangy

   Oppositesweet

   Note

   The taste sense carries the word's Latin core: French acide, from Latin acidus "sour," built on aceō, "I am sour." Acetic comes from the same Latin family, which helps explain why vinegar turns up in the definition. The adjective sits comfortably beside foods and drinks, as in acid fruits or acid liquors, and it names a taste that bites, not one that simply lacks sweetness.

6. 6
   adjective

   Relating to or having the properties of an acid; acidic.

   The reaction produced an acid solution with a low pH.

   Acid rain damaged the forests downwind of the plant.

   Similaracidic

   Oppositealkaline, basic

7. 7
   adjectivefiguratively

   Bitter, sharp, or cutting in temperament or expression; sour-tempered.

   The critic's wit could turn acid in an instant.

   She shot back an acid retort and walked out.

   Similaracerbic, caustic, biting, cutting, sharp

   Oppositegentle, kind

   Note

   Taste turns into temperament: what bites the tongue in the sour-taste meaning here bites the listener. Its favorite partners are speech and expression. Conan Doyle's Summerlee in The Lost World (1912) "has an acid tongue," and Trollope in 1864 gives a face "as acid as ever." It works before a noun (an acid tongue) and after a verb (his response was harsh and acid).

8. 8
   nouncountable or uncountable

   Any compound that readily donates protons to a base, known in chemistry as a Brønsted acid.

   In the reaction, the acid donates a proton to ammonia and leaves a chloride ion behind.

   Carboxylic compounds donate protons and so behave as acids.

   Oppositebase

   Note

   Here acidity is a relationship, not a fixed property: a compound is a Brønsted acid only toward a base that takes its proton. Whatever remains once the proton leaves is called its conjugate base, so every acid of this kind comes paired. Because the exchange needs no water, this definition reaches reactions that the water-bound definition cannot describe.

9. 9
   nouncountable or uncountable

   In chemistry, any substance able to take up a pair of electrons from another species and so form a covalent bond, as defined by Lewis.

   A Lewis acid takes on an electron pair from a base, forming a covalent bond.

   Boron compounds frequently behave as acids by accepting electron pairs.

   Oppositebase

   Note

   The Lewis framework casts the widest net. An acid of this kind need not hold a proton at all, only room to accept an electron pair from a donor. Boron trifluoride is the classic case: an acid with no hydrogen to give. Because both electrons in the resulting bond come from the partner, chemists often call it a coordinate covalent bond.

10. 10
    adjective

    Denoting a musical genre that distorts an existing style as if through a hallucinogenic lens, as in acid house, acid jazz, and acid rock.

    The DJ built his set around classic acid house tracks.

    Acid rock defined much of the late-sixties psychedelic scene.

    Note

    Musicians and fans attach this label to the front of an existing genre name: acid house, acid jazz, acid rock. The added word signals a warped, hallucinatory take on the parent style, and that image comes from the slang name for LSD. It works as a fixed modifier and is not graded the way an acid taste is. Each pairing is best treated as a genre name in its own right.

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