acid

noun

\ ˈa-səd

Definition of acid

(Entry 1 of 2)

1 : a sour substance specifically : any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base (see base entry 1 sense 6a) to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base

2 : something incisive, biting, or sarcastic a social satire dripping with acid

3 : lsd

acid

adjective

Definition of acid (Entry 2 of 2)

1a : sour, sharp, or biting to the taste an acid flavor

b : sharp, biting, or sour in manner, disposition, or nature an acid individual an acid personality

c : sharply clear, discerning, or pointed an acid wit acid criticism

d : piercingly intense and often jarring acid yellow

2a : of, relating to, or being an acid also : having the reactions or characteristics of an acid acid soil an acid solution

b of salts and esters : derived by partial exchange of replaceable hydrogen acid sodium carbonate NaHCO₃

c : containing or involving the use of an acid (as in manufacture) an acid bath

d : marked by or resulting from an abnormally high concentration of acid acid indigestion

3 : relating to or made by a process in which the furnace is lined with acidic material and an acidic slag is used acid steel

4 : rich in silica acid rocks

Other Words from acid Synonyms More Example Sentences Learn More about acid

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Other Words from acid

Noun

acidy \ ˈa-sə-dē \ adjective

Adjective

acidly adverb

acidness noun

Examples of acid in a Sentence

Noun

the acids in your stomach the kinds of acid found in your stomach

Adjective

He washes his windows with an acid solution of vinegar and water. with her acid personality, my aunt could be relied upon to bring some much-needed balance to the holiday gush

Recent Examples on the Web: Noun

Her client’s father was murdered for his political work, said Corchado, and his sister attacked with acid. — Cedar Attanasio, Washington Post, "Attorney: Officials force-feeding immigrant on hunger strike," 15 Aug. 2019 Our signs and ones like them have been stolen, thrown in the river, replaced, shot, replaced again, shot again, defaced with acid and have had KKK spray painted on them. — Nicole Chavez, CNN, "University of Mississippi students were suspended after posing in front of an Emmett Till memorial sign with guns," 25 July 2019 The woman and her daughter’s attack came just months after a teenage girl was attacked with acid in April after trying to escape gang rape. — Fox News, "Men beat, shaves heads of mother-daughter duo who resists sexual assault as punishment," 28 June 2019 And a fun bonus, the deep blue-green hue of borage simple syrup turns a gorgeous shade of purple when combined with acid. — Paul Stephen, ExpressNews.com, "Use floral simple syrups in your cooking, not just cocktails," 19 June 2019 Marble’s aforementioned issue with acids generally makes white the wisest choice for a countertop installation, because the shade is less likely to show the etching and scratches that can occur. — Kelly Dawson, House Beautiful, "Everything You Need to Know About Having a Marble Countertop," 5 Feb. 2019 Chlorine gas is made by mixing chlorine with an acid. — Kyle Mizokami, Popular Mechanics, "U.S. Soldier Found Guilty of Building, Exploding Poison Gas Bomb," 26 Sep. 2018 In the 1960s, Charles Manson plied his followers with acid at nearby Barker Ranch. — J. Weston Phippen, Outside Online, "People Keep Finding Bodies in Joshua Tree," 20 June 2018 Removing the objects and washing the sheet with an acid leaves a kind of engraved plate that can be used to make prints. — The Economist, "Retro photography is in vogue," 2 June 2018

Recent Examples on the Web: Adjective

That unpleasant burning sensation (and sometimes taste) in your throat and/or chest is known as gastroesophageal reflux (i.e. acid reflux or heartburn). — Carolyn L. Todd, SELF, "Is Late-Night Snacking Really So Wrong?," 23 Aug. 2019 According to Acid Survivors Trust International, there are more than 1,500 recorded acid attacks globally and 80% of those target women. — Suddaf Kauser Chaudry, CNN, "Artificial skin trial offers hope to Pakistan's acid attack victims," 3 July 2019 One high in animal protein such as beef, chicken, fish and pork may increase acid levels in the urine because meat breaks down into uric acid, which can help form stones. — Marcos Del Rosario-santiago, baltimoresun.com, "Doctors say summer is kidney-stone season. Here’s what you should know.," 11 July 2019 First, an image is rendered in greasy, acid-repelling ink on a slab of limestone. — Hua Hsu, The New Yorker, "How Posters Became Art," 1 July 2019 That, and medication for acid reflux, made Chayton a much happier baby. — Alix Boyle, courant.com, "Babies learning sign language: Promotes communication, bonding and verbal skills," 16 July 2019 The dramatic spring blooming dogwoods prefer the sandy, acid soil of East Texas but will perform well in the black soils if planted in prepared beds. — Howard Garrett, Dallas News, "Not big on big trees? These little ones grow well in sun and shade," 9 July 2019 The acid smell of everything that gets sweat out along the way. — Andrea Pitzer, Outside Online, "I (Kinda) Hate Running," 9 July 2019 One high in animal protein such as beef, chicken, fish and pork may increase acid levels in the urine because meat breaks down into uric acid, which can help form stones. — Marcos Del Rosario-santiago, chicagotribune.com, "Doctors say summer is kidney-stone season. Here’s what you should know.," 1 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'acid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

History and Etymology for acid

Noun

borrowed from Medieval Latin acidum, going back to Latin, neuter of acidus acid entry 2

Adjective

borrowed from French & Latin; French acide, going back to Middle French, borrowed from Latin acidus, adjective derivative from the base of acēre "to be sour" — more at acetic acid

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Dictionary Entries near acid

Statistics for acid

Last Updated

17 Sep 2019

Look-up Popularity

Time Traveler for acid

The first known use of acid was in 1649

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More Definitions for acid

acid

noun

English Language Learners Definition of acid

(Entry 1 of 2)

chemistry : a chemical with a sour taste that forms a salt when mixed with a base

acid

adjective

English Language Learners Definition of acid (Entry 2 of 2)

: of, relating to, or having the qualities of an acid

: sharp, strong, and critical in tone

See the full definition for acid in the English Language Learners Dictionary

acid

adjective

ac·id | \ ˈa-səd

Kids Definition of acid

(Entry 1 of 2)

1 : having a taste that is sour, bitter, or stinging

2 : harsh or critical in tone acid remarks

3 : of, relating to, or like an acid an acid solution

acid

noun

Kids Definition of acid (Entry 2 of 2)

: a chemical compound that tastes sour and forms a water solution which turns blue litmus paper red

acid

adjective

ac·id | \ ˈas-əd

Medical Definition of acid

(Entry 1 of 2)

1 : sour, sharp, or biting to the taste

2a : of, relating to, or being an acid also : having the reactions or characteristics of an acid an acid solution

b of salts and esters : derived by partial exchange of replaceable hydrogen acid sodium carbonate NaHCO₃

c : marked by or resulting from an abnormally high concentration of acid acid indigestion —not used technically

acid

noun

Medical Definition of acid (Entry 2 of 2)

1 : a sour substance specifically : any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base to form a salt, that redden litmus, that have a pH less than 7, and that are hydrogen-containing molecules or ions able to give up a proton to a base or are substances able to accept an unshared pair of electrons from a base

2 : lsd