acetic acid

noun

ace·​tic acid ə-ˈsē-tik- 

: a colorless pungent liquid acid C₂H₄O₂ that is the chief acid of vinegar and that is used especially in synthesis (as of plastics)

Examples of acetic acid in a Sentence

Recent Examples on the Web

Kitchen vinegar is 5 percent acetic acid and works best on tiny weeds that have sprouted one or two leaves. —Brandee Gruener, Southern Living, 2 July 2025

Lead from the anode is mixed with nitric acid and the lead oxide (made from the lead dioxide cathode) is mixed in acetic acid. —IEEE Spectrum, 19 Aug. 2014

Kefir grains composition: Kefir grains are gel-like substances made from lactic acid bacteria, yeast, acetic acid bacteria, and polysaccharides (a type of carbohydrate). —Melissa Nieves, Verywell Health, 11 June 2025

Household vinegar, which is rather weak (5% acetic acid), does not travel to the roots. —Patricia Shannon, Southern Living, 17 June 2025

Word History

Etymology

acetic borrowed from French acétique, from Latin acētum "sour wine, vinegar" (noun derivative from *acētus, verbal adjective of acēre "to be sour," going back to Indo-European h₂eḱ-eh₁- "to be sharp") + French -ique -ic entry 1 — more at edge entry 1

First Known Use

1788, in the meaning defined above

Rhymes for acetic acid

• antacid
• placid

Kids Definition

acetic acid

noun

: a colorless strong-smelling liquid acid that gives the sour taste to vinegar and that is used especially in making chemical compounds (as plastics)

Medical Definition

acetic acid

noun

: a colorless pungent liquid acid C₂H₄O₂ that is the chief acid of vinegar and that is used especially in synthesis (as of plastics) and occasionally in medicine as an astringent and styptic