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

That is until Sullivan and his girlfriend took acid on a trip to Alaska and God spoke to him. — Debra Borchardt, chicagotribune.com, "Top 5 cannabis industry scandals," 6 Sep. 2019 Horticultural vinegar, which is used to kill weeds, is 20% acetic acid. — oregonlive.com, "Can household vinegar kill dandelions? Ask an expert," 17 Aug. 2019 Add a little acid — think lemon juice or vinegar — to make a dressing for salads or a sauce for steak or fish. — NBC News, "How to make the perfect pesto — and 5 recipes to get you started," 15 Aug. 2019 Are crape myrtles like hydrangeas, where adding acid to the soil will change the flower color? — Neil Sperry, ExpressNews.com, "If you want more figs, don’t prune your trees," 2 Aug. 2019 In Ceuta, after some migrants threw battery acid at Spanish police during the August border breach, some residents were on edge. — Jeannette Neumann, WSJ, "As Migrants Turn to Spain, a Welcome Mat Shows Signs of Wear," 23 Sep. 2018 This is a chain of eight carbon atoms, seven of which have fluorine atoms attached to them; the eighth is linked to two oxygen atoms, typical of an organic acid. — John Timmer, Ars Technica, "EPA boots reporters from meeting on chemicals called a PR disaster," 22 May 2018 Pollan had his whole life to try psychedelics, but for the baby boomer journalist, there was no dropping acid in the parking lot of a Grateful Dead show in the 1970s or anything like that. — Jason Diamond, The New Republic, "Can Psychedelic Drugs Do Good?," 15 May 2018 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

Recent Examples on the Web: Adjective

An intense whirligig of tannins metallically attacked my mouth and, on the finish, there was an astringent sizzle, with undertones of acid reflux. — Troy Patterson, The New Yorker, "How the Orange-Wine Fad Became an Irresistible Assault on Pleasure," 7 Sep. 2019 The syrups were supposed to include the drug omeprazole, a common drug to treat acid reflux. — Beth Mole, Ars Technica, "Hairy “werewolf syndrome” in babies and kids caused by drug mix-up," 29 Aug. 2019 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

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

1 Oct 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