I. ˈasə̇d, ˈaa- adjective
Etymology: French or Latin; French acide, from Latin acidus, from acēre to be sour — more at acute
1.
a. : sharp or biting to the taste
acid lemons
: sour , tart
the acid juice of unripe grapes
an acid apple
b. : sharp, biting, or sour in manner, disposition, or nature
his acid way of dealing with people
an acid misanthrope
: prone to antagonize, wound, or humiliate : repellently disagreeable : unpleasant , offensive
an acid individual, unable to get along with anyone
: cutting , caustic
acid remarks
acid gibes
: corrosive
acid hatred
c. : sharply clear, discerning, pointed, and usually more or less mocking or sarcastic
acid criticism
an acid analysis of the situation
acid wit
: penetrating , trenchant , incisive : quick in perception
his cold and acid intelligence
: shrewd , acute
d. : severe and uncompromising : harsh , rigid , inflexible , unyielding
a censorious and acid attitude toward freedom of thought
e. : piercingly intense
the acid radiance of the bright sunlight
and often jarring
acid splashes of brilliant yellows
or shrill
a singing voice that unfortunately becomes sometimes acid in the upper register
2. : of, relating to, or having the characteristics of an acid: as
a. : having an acid reaction : having a pH of less than 7
acid soil
a slightly acid solution
b.
(1) : derived from an acid
acid iodide
(2) of salts and esters : derived by partial exchange of replaceable hydrogen
acid potassium sulfate KHSO 4
c. : containing or involving the use of an acid
acid bath
acid sludge
acid hydrolysis
d. : characterized by or resulting from an abnormally high concentration of acid
acid condition of the stomach
acid indigestion
— not used technically
e. : relating to or made by an acid process
acid steel
3. : rich in silica : persilicic
acid rocks
— opposed to basic
Synonyms: see sour
II. noun
( -s )
Etymology: New Latin acidum, from Latin, neuter of acidus, adjective
1. : a sour substance
2.
a. : a compound (as hydrochloric acid, sulfuric acid, or benzoic acid) capable of reacting with a base to form a salt, its aqueous solutions if it is water-soluble tasting sour, reddening litmus, and evolving hydrogen on reaction with certain metals (as iron, zinc, tin) : a compound (HX) containing hydrogen that in aqueous solution yields hydrogen ion (H + ) hydrated to hydronium ion (as H 3 O + ), together with the anion (X - ), the degree of ionization in dilute solutions of strong acids (as nitric, hydrochloric, or trichloroacetic acid) being virtually complete, that of weak acids (as acetic or benzoic acid) being possibly one percent, and that of very weak acids (as hydrocyanic or boric acid) being much less than one percent — compare hydrogen-ion concentration , ph
b. according to the Brønsted-Lowry system : a hydrogen-containing molecule (as nitric acid) or ion (as hydronium, ammonium, or bicarbonate) that can give up a proton to a base : a proton donor
hydrogen chloride is the conjugate acid of the chloride ion
c. according to the G.N.Lewis system : a substance capable of accepting from a base an unshared pair of electrons which then form a covalent chemical bond, many compounds (as boron fluoride, sulfur trioxide, or carbon dioxide) as well as protons and other positive ions being thus included in this class — called also Lewis acid
3. : dilute sulfuric acid used in storage batteries
4. : something sharp, biting, sour, or corrosive
a social satire dripping with acid
destroying freedom with the acid of narrow-mindedness
III. noun
: lsd