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 microbes that typically consume acetic acid had disappeared, yet methane production kept flowing. —Georgina Jedikovska, Interesting Engineering, 24 Oct. 2025

Apple Cider Vinegar Apple cider vinegar contains acetic acid, which can alter the pH balance of urine. —Md Published, Verywell Health, 20 Oct. 2025

The remaining 40 percent is molecularly recycled materials such as plastic packaging and carpets that are turned into acetic acid. —Sarah Jones, Sourcing Journal, 20 Oct. 2025

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

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