acid

noun

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
ac·​id | \ ˈa-səd How to pronounce acid (audio) \

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

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Other Words from acid

Noun

acidy \ ˈa-​sə-​dē \ adjective

Adjective

acidly adverb
acidness noun

Synonyms for acid

Synonyms: Adjective

acidic, acidulous, sour, sourish, tart, tartish, vinegary

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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
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Recent Examples on the Web: Noun

My husband recently had an endoscopy that revealed an anomalous patch of stomach tissue on the wall of his esophagus which had been exacerbating his acid reflux. Bobby Finger, New York Times, "Is Cold Brew Better Than Iced Coffee?," 2 July 2019 The acid attack was the final blow in a long and abusive relationship. Jane Tyska, The Mercury News, "Local Richmond domestic abuse survivor helps victim of Ethiopian acid attack," 23 June 2019 As early as 2010, police used such data to track down a suspect in an acid-attack case, who was later convicted. Mary Hui, Quartz, "Why Hong Kong’s protesters were afraid to use their metro cards," 13 June 2019 Under Indian law, perpetrators of acid attacks face a minimum of 10 years in prison. San Diego Union-Tribune, "Column One: This cafe in India is fully run by acid attack survivors," 18 Apr. 2019 President Petro Poroshenko has lamented Ms. Handzyuk’s death following an acid attack as a tragedy and defended the investigation as thorough. James Marson, WSJ, "Justice Remains Elusive in Ukraine, Widening Door to Russian Influence," 28 Dec. 2018 In 1956, a columnist in New York was blinded in an acid attack following his coverage of gangsters and corruption. Anna Orso, Philly.com, "Following Annapolis shooting, journalists contemplate angry readers, death threats and backlash," 29 June 2018 This recall was due to unacceptable amounts of N-Nitroso-N-methyl-4-aminobutyric acid or NMBA. Jen Christensen, CNN, "Pharmacy tests turn up another cancer-causing compound in heart drugs," 18 June 2019 Then the final component of Garrett Juice came about after an arborist buddy of mine discovered that adding a pH-lowering acid to his fish and seaweed sprays helped make the ingredients more bio-available to plants in his oak wilt work. Howard Garrett, Dallas News, "How to make this do-it-yourself organic fertilizer and pest control spray," 18 June 2019

Recent Examples on the Web: Adjective

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 But the team’s earned run average this year is acid reflux-inducing 5.10, which ranks dead last in the National League. Mark Kiszla, The Denver Post, "Kiszla: All-star David Dahl a smash hit for Rockies, but can Blake Street Bombers 2.0 slug their way to playoffs?," 30 June 2019 Soil Beets grow best in loamy, acid soils (pH levels ranging between 6.0 and 7.5). The Editors, Good Housekeeping, "How to Grow Beets This Fall for a Hearty Autumn Harvest," 21 Aug. 2018 The manager of Sheroes’ Hangout is Rupa Saa, another acid attack survivor. San Diego Union-Tribune, "Column One: This cafe in India is fully run by acid attack survivors," 18 Apr. 2019 Finally, waste-to-energy plants have the potential to emit low levels of toxic pollutants such as dioxins, acid gases, and heavy metals. Elizabeth Royte, National Geographic, "Is burning plastic waste a good idea?," 12 Mar. 2019 Not only is your metabolism chugging along, but lying down can also contribute to acid reflux. Caroline Picard, Good Housekeeping, "15 Ways to Sleep Better Tonight, According to Experts," 2 May 2019 According to Friedler, the only way to do that is to traumatize the collagen with laser treatments, acid peels or retinoids. Elizabeth Kiefer, The Seattle Times, "Jade rollers: Puffy-eye wonder cure or sham?," 26 Mar. 2019 During the Reagan era, acid-wash jeans were, for a brief period, inescapable. Janelle Okwodu, Vogue, "Are You Ready for the Return of Acid-Wash Jeans? Katy Perry Is," 6 Aug. 2018

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.

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First Known Use of acid

Noun

1650, in the meaning defined at sense 1

Adjective

1649, in the meaning defined at sense 1a

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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Statistics for acid

Last Updated

9 Jul 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

acid

adjective
ac·​id | \ ˈa-səd How to pronounce acid (audio) \

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

Other Words from acid

acidly adverb spoke acidly

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 How to pronounce acid (audio) \

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

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More from Merriam-Webster on acid

Rhyming Dictionary: Words that rhyme with acid

Thesaurus: All synonyms and antonyms for acid

Spanish Central: Translation of acid

Nglish: Translation of acid for Spanish Speakers

Britannica English: Translation of acid for Arabic Speakers

Britannica.com: Encyclopedia article about acid

Comments on acid

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