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

The shiitake mushrooms, with their shock of acid, are the exception. Washington Post, "Zeppelin is fun, but its sushi doesn’t quite fly," 1 Aug. 2019 Five car batteries got dumped on the ground, causing a minor spill of battery acid, the California Highway Patrol’s incident log said. Pauline Repard, San Diego Union-Tribune, "Overturned truck blocks lanes of north I-15 near Miramar Road," 26 July 2019 Pickled grapes stud this dish providing a pop of acid to balance the overall earthiness of the protein and vegetables. Anchorage Daily News, "Former ‘Top Chef’ contestant and James Beard-nominated chef takes over Muse restaurant. So: how’s the food?," 17 July 2019 Thanks to the wide range of brewing methods, the difference in caffeine content among cold brews is considerably harder to predict than the amount of acid. Bobby Finger, New York Times, "Is Cold Brew Better Than Iced Coffee?," 2 July 2019 Vibrant orange sweet potato gnocchi, with a playfully non-traditional chew, sit in a thick, almost sticky chicken reduction cut with just a touch of acid. Dominic Armato, azcentral, "The best restaurants in Scottsdale and Paradise Valley," 1 July 2019 Worries over the the risks of hydroflouric acid have only heightened since. Tony Barboza, latimes.com, "Air quality committee rejects ban on toxic acid used in South Bay refineries," 22 June 2019 Mirrors, the top and back of the bar, and brass tables were acid washed to create a vintage look. Shauna Stuart | Sstuart@al.com, al.com, "In Founder’s Station, Cayo Coco Rum Bar & Restaurante is a nod to Cuba’s pre-revolution high life," 12 July 2019 Sides round out all that meat with acid (pickles!), crunch (slaw!), carbs (mac and cheese!). Emily Schultz, Bon Appétit, "I Didn’t Know Collard Greens Could Taste Like This Until I Went to Buxton Hall," 11 July 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, 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 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

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

6 Aug 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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