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

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Synonyms for acid

Synonyms: Adjective

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 Many restaurants take those less-than-beautiful vegetables and scraps and make wholesome stocks and broths or preserve them by drying them in a dehydrator or oven, or pickle or ferment them using salt or acid. — San Diego Union-Tribune, "Delicious, not discarded: Get more out of your fresh produce," 14 Apr. 2021 Risk factors include obesity, smoking, poor diet and chronic acid reflux. — Anna Kuchment, Dallas News, "New drug doubles disease-free survival in esophageal cancer," 31 Mar. 2021 And the tartar sauce — on the top and bottom of the fish — adds acid and moisture to every bite. — Jenn Harris Columnist, Los Angeles Times, "The fried fish sandwich gets an upgrade at these L.A. restaurants," 24 Mar. 2021 Face oils mimic the body’s natural oils and sebum, often replenishing the necessary lubricant lost after harsh cleansing and acid toning. — Tanya Akim, Forbes, "The 5 Best Face Oils To Use In 2021," 11 Mar. 2021 During installation, the cells would be filled with acid and the battery would be charged. — Motormouth Bob Weber, Star Tribune, "Motormouth: Go with ethanol-free gas during storage," 19 Feb. 2021 The acid typically dissipates in spring and summer, but with levels this high there’s no assurance of a reopening any time soon. — oregonlive, "Bill Monroe: The outdoors offers relief amid a challenging time," 2 Apr. 2021 Not gullible, lost, or nihilists, my parents knew better than to share the acid with the children. — Rachel Kushner, Vogue, "A Technicolored Childhood on the Bus My Parents Made a Home," 16 Mar. 2021 This was debunked in November 2000 by Snopes, which found that the gastric acid in your stomach's digestive fluid is stronger than any of the acids that are contained in Coca-Cola. — Mckenzie Sadeghi, USA TODAY, "Fact check: Pouring Coca-Cola on pork does not make worms appear," 16 Mar. 2021 Recent Examples on the Web: Adjective After falling in love with club music (and its drugs) heading into 1988, McGee then championed Manchester’s burgeoning acid-house scene that blurred the lines between rock, psychedelia, and dance. — Brady Gerber, Vulture, "Creation Records, the Label History Loves to Overlook," 29 Mar. 2021 While the all-over powder look couldn’t be more out of style than acid wash jeans, this satiny loose powder is great for lightly dusting over your T-zone to set foundation and eliminate any shine. — Kaitlyn Yarborough, Southern Living, "This $16 Foundation Brush Has Shoppers Getting Rid of Their Bacteria-Ridden Makeup Sponges For Good," 18 Mar. 2021 The shells were decorated using an acid etching technique that O'odham artists still use in contemporary shell pieces. — Debra Utacia Krol, The Arizona Republic, "Archaeologic finds in Mesa, Tempe connect the history of O'odham peoples' history to present day," 6 Mar. 2021 Inspired by ’90s Los Angeles street style, cargo pants, acid hues and sporty stripes make a rebound for spring. — New York Times, "Nostalgic Looks With a Breezy California Vibe," 4 Mar. 2021 Acid pink cloud puffer coats are the culmination of a three-season story of cloudscapes, from clear blue skies to putrid, acid green and pastel pink to represent the sunset. — Steff Yotka, Vogue, "Phlemuns Releases a Spring Collection for Your Body—And Your Mind," 2 Mar. 2021 Coffee isn't for everyone, including those who suffer from acid reflux, sleep disorders or sleep hygiene concerns, anxiety, or more simply a dietary sensitivity to caffeine. — Stefani Sassos, Ms, Rdn, Cso, Good Housekeeping, "12 Ways Coffee May Boost Your Health and Wellness, According to Research," 1 Mar. 2021 The series might have climbed from the brain of a woke English grad student on an acid trip. — Katy Waldman, The New Yorker, "Alena Smith’s Subversive “Dickinson”," 25 Feb. 2021 These pillows are typically used to help alleviate symptoms of acid reflux, gastroesophageal reflux disease (GERD), and obstructive sleep apnea. — Jamie Kim, Good Housekeeping, "Every Type of Pillow You Need to Know About," 18 Feb. 2021

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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Last Updated

18 Apr 2021

Cite this Entry

“Acid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/acid. Accessed 18 Apr. 2021.

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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

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