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

The live ants consistently introduced lactic acid, as well as acetic acid, to the milk, and the live ant yogurt contained several species of lactic acid bacteria, according to the study. —Amarachi Orie, CNN Money, 3 Oct. 2025

It was found that the ants contained lactic and acetic acid bacteria. —Mrigakshi Dixit, Interesting Engineering, 3 Oct. 2025

Now, researchers have found the particles in their study could help to kill several dangerous bacterial species, an ability enhanced when added to a weak acetic acid. —Hannah Millington, MSNBC Newsweek, 23 Sep. 2025

The main active ingredient in apple cider vinegar is acetic acid. —Morgan Pearson, Verywell Health, 15 Sep. 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