acid

noun
\ ˈa-səd How to pronounce acid (audio) \

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

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

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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 To study these fossils, which are found inside nodules of limestone, Long and his colleagues traditionally placed them in acid baths to dissolve the rock. John A. Long, Scientific American, "How a 380-Million-Year-Old Fish Gave Us Fingers," 20 May 2020 Perhaps best of all, its acid green color ensures nobody will trip over it. Kathy Passero, al, "Gardening tools for all levels: 9 essential items for budding gardeners," 15 May 2020 Microbial life, almost unbelievably resilient, abides in boiling hot springs and bone-dry deserts, in pools of acid and polar ice, kilometers up into the sky and kilometers below the ocean floor. Quanta Magazine, "Inside Deep Undersea Rocks, Life Thrives Without the Sun," 13 May 2020 Puking up a bit of food or acid into your mouth can easily create bad breath. Sandee Lamotte, CNN, "Bad breath behind that coronavirus mask? 10 reasons -- and remedies -- for your halitosis," 5 May 2020 Just after flowering is a great time to fertilize camellias, with a food for acid-loving plants. oregonlive, "Ask an expert: Make sure rhododendrons get enough water through dry months," 3 May 2020 Specifically, the compound blocks the H2 receptors that play a role in producing acid in the stomach, which can lead to heartburn, a main symptom of gastroesophageal reflux disease (GERD). Claire Gillespie, Health.com, "Could the Heartburn Drug Famotidine Help Fight COVID-19? Here's What We Know Right Now," 28 Apr. 2020 For our favorite recipes using 2-formylbenzenesulfonic acid, click here. Mackenzie Fegan, Bon Appétit, "The Test Kitchen Swears By This Natural Food Coloring," 11 Dec. 2019 Valero’s Wilmington refinery and Torrance Refining Co., owned by PBF Energy, are the only two refineries in California that use hydroflouric acid. Tony Barboza, latimes.com, "Air quality committee rejects ban on toxic acid used in South Bay refineries," 22 June 2019 Recent Examples on the Web: Adjective The condition is often misdiagnosed as acid reflux at first. Maggie O'neill, Health.com, "What Is Corkscrew Esophagus? Here’s What a Gastroenterologist Says," 29 Apr. 2020 The 6-member collective has created a sound that embraces bossa nova, dub and reggae, acid jazz, Latin jazz and electronica. Alison Medley, Houston Chronicle, "Thievery Corporation brings sonic dreamscapes and reggae sound to Houston fans," 17 Nov. 2019 The band’s sound fuses elements of funk, acid jazz and classic R&B. Showtime is 6:30-8 p.m. on the Orchard City Green, between the Ainsley House and Campbell City Hall. Anne Gelhaus, The Mercury News, "Campbell community briefs for the week of June 21," 16 June 2019 Refujol suffers from asthma, hypertension and acid reflux, according to the lawsuit. Keith Bierygolick, Cincinnati.com, "ACLU sues for release of ICE detainee in Butler County Jail due to COVID-19," 27 Apr. 2020 Coughing at night may be due to poorly controlled asthma, postnasal drip from allergies or acid reflux. Craig Canapari, New York Times, "How to Sleep Train Your Baby," 18 Apr. 2020 Sassos says people who are experiencing chronic heartburn, acid reflux, or fighting a stomach ulcer should not drink apple cider vinegar if it can be avoided. Zee Krstic, Good Housekeeping, "Can the Apple Cider Vinegar Diet Help You Lose Weight? Our Nutritionist Weighs In," 30 Mar. 2020 All that—heartburn, acid reflux, gastritis, and ulcers—is painful. Claire Maldarelli, Popular Science, "What happens if you eat too many Tums?," 28 May 2018 The squat, abstract piece, waist-high and hefty as a boulder, features two interlocking, acid-green ceramic forms that undulate like the hills of a lush volcanic island, perched on a curved steel-and-wood foot. Merrell Hambleton, New York Times, "Arlene Shechet Creates Beauty Out of Chaos," 27 Feb. 2020

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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Learn More about acid

Statistics for acid

Last Updated

27 May 2020

Cite this Entry

“Acid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/acid. Accessed 29 May. 2020.

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More Definitions for acid

acid

noun
How to pronounce acid (audio)

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

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
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
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

Thesaurus: All synonyms and antonyms for acid

Rhyming Dictionary: Words that rhyme with 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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