acid

noun

Chemistry. a compound usually having a sour taste and capable of neutralizing alkalis and reddening blue litmus paper, containing hydrogen that can be replaced by a metal or an electropositive group to form a salt, or containing an atom that can accept a pair of electrons from a base. Acids are proton donors that yield hydronium ions in water solution, or electron-pair acceptors that combine with electron-pair donors or bases.

a substance with a sour taste.

something, as a remark or piece of writing, that is sharp, sour, or ill-natured: His criticism was pure acid.

Slang. LSD ( def 2 ).

adjective

Chemistry.

belonging or pertaining to acids or the anhydrides of acids.

having only a part of the hydrogen of an acid replaced by a metal or its equivalent: an acid phosphate.

having a pH value of less than 7. Compare alkaline ( def 4 ).

sharp or biting to the taste; tasting like vinegar; sour: acid fruits.

sharp, biting, or ill-natured in mood, manner, etc.: an acid remark; an acid wit.

Geology. containing much silica.

Metallurgy. noting, pertaining to, or made by a process in which the lining of the furnace, or the slag that is present, functions as an acid in high-temperature reactions in taking electrons from oxide ions: usually a siliceous material, as sand or ganister. Compare basic ( def 3 ).

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Acid is always a great word to know.

So is cyanide. Does it mean:

having an unsymmetrical arrangement of atoms in a molecule, or noting a carbon atom bonded to four different atoms or groups

a salt of hydrocyanic acid, such as potassium cyanide, KCN

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Idioms

10.

put on the acid, Australian Slang. to importune someone, as for money, sexual favors, or confidential information.

Origin:
1620–30; < Latin acidus sour, akin to ācer sharp, acētum vinegar, acescent, acicula

Related forms

ac·id·ly, adverb

ac·id·ness, noun

non·ac·id, noun, adjective

pre·ac·id, adjective

pre·ac·id·ness, noun

sem·i·ac·id, adjective

Can be confused: acerbic, acid, acrid.

Synonyms
7. acerbic, stinging, vitriolic, tart. Acid, astringent are terms used figuratively of wit or humor. Acid suggests a sharp, biting, or ill-natured quality: an acid joke about an opponent. Astringent connotes severity but usually also a bracing quality, as of something applied with curative intent: astringent criticism.

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
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Link To Acid

Collins

World English Dictionary

acid (ˈæsɪd)

—n
1.	See also Lewis acid any substance that dissociates in water to yield a sour corrosive solution containing hydrogen ions, having a pH of less than 7, and turning litmus red
2.	a sour-tasting substance
3.	a slang name for LSD

—*adj*
4.	chem
	a. of, derived from, or containing acid: an acid radical
	b. being or having the properties of an acid: sodium bicarbonate is an acid salt
5.	sharp or sour in taste
6.	cutting, sharp, or hurtful in speech, manner, etc; vitriolic; caustic
7.	(of rain, snow, etc) containing pollutant acids in solution
8.	(of igneous rocks) having a silica content of more than 60% of the total and containing at least one tenth quartz
9.	metallurgy of or made by a process in which the furnace or converter is lined with an acid material: acid steel

[C17: (first used by Francis Bacon): from French acide or Latin acidus, from acēre to be sour or sharp]

'acidly

—*adv*

'acidness

—n

'acidy

—*adj*

Acid House or Acid

—n
	a type of funk-based electronically edited disco music of the late 1980s, which has hypnotic sound effects and is associated with hippy culture and the use of the drug ecstasy

[C20: perhaps from acid (LSD) + House (music)]

Acid or Acid

—n

[C20: perhaps from acid (LSD) + House (music)]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline

Word Origin & History

acid

1620s, from Fr. acide, from L. acidus "sour," adj. of state from acere "to be sour," from PIE base *ak- "sharp, pointed" (see acrid). Applied to intense colors from 1916. Slang meaning "LSD-25" first recorded 1966 (see LSD); acid rock (type played

by or listen to by people using LSD) is also from 1966; acid house dance music style is 1988, probably from acid in the hallucinogenic sense + house "dance club DJ music style." Acid test is Amer.Eng., 1892, from the frontier days, when gold was distinguished from similar metals by application of nitric acid. Acid rain is first recorded 1859 in ref. to England. Adj. acidic is attested from 1877, originally in geology.

When I was on acid I would see things that looked like beams of light, and I would hear things that sounded an awful lot like car horns. [Mitch Hedberg, 1968-2005, U.S. stand-up comic]

Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage

Medical Dictionary

acid ac·id (ās'ĭd)
n.

Any of a large class of sour-tasting substances whose aqueous solutions are capable of turning blue litmus indicators red, of reacting with and dissolving certain metals to form salts, and of reacting with bases or alkalis to form salts.
A substance that ionizes in solution to give the positive ion of the solvent.
A substance capable of yielding hydrogen ions.
A proton donor.
An electron acceptor.
A molecule or ion that can combine with another by forming a covalent bond with two electrons of the other.
A substance having a sour taste.
See LSD.

adj.

Of or relating to an acid.
Having a high concentration of acid.
Having a sour taste.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage

Science Dictionary

acid

(ās'ĭd) Pronunciation Key
Any of a class of compounds that form hydrogen ions when dissolved in water, and whose aqueous solutions react with bases and certain metals to form salts. Acids turn blue litmus paper red and have a pH of less than 7. Their aqueous solutions have a sour taste. Compare base.

acidic adjective

American Heritage

Cultural Dictionary

acid definition

A sour-tasting material (usually in a solution) that dissolves metals and other materials. Technically, a material that produces positive ions in solution. An acid is the opposite of a base and has a pH of 0 to 7. A given amount of an acid added to the same amount of a base neutralizes the base, producing water and a salt. Common vinegar, for example, is a weak solution of acetic acid.

Note: Figuratively, acid applies to anything sour or biting; for example, an “acid wit” is sharp and unpleasant.

Slang Dictionary

acid definition

n.
lysergic acid diethylamide (LSD). (Drugs.) : Freddy got hold of some bad acid and freaked out.

Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition.
Copyright 2007. Published by McGraw Hill.
Cite This Source

FOLDOC

Computing Dictionary

ACID definition

programming
A mnemonic for the properties a transaction should have to satisfy the Object Management Group Transaction Service specifications. A transaction should be Atomic, its result should be Consistent, Isolated (independent of other transactions) and Durable (its effect should be permanent).
The Transaction Service specifications which part of the Object Services, an adjunct to the CORBA specifications.
(1997-05-15)

American Heritage

Abbreviations & Acronyms

ACID
aircraft identification

Example sentences

And it does so by activating this acid-sensing protein.

Because of the sulfur acid, one camera broke down-the acid damaged all the

copper contacts.

No acid trips, no homemade special effects, not a curlicue of camp.

So the amino acid chain is surrounded by water molecules.

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picric acid alpha-ketoglutaric acid aminobenzoic acid benzoic acid chloroacetic acid coenzyme A

Matching Quote

"Tobacco, coffee, alcohol, hashish, prussic acid, strychnine, are weak dilutions: the surest poison is time."

-Ralph Waldo Emerson