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

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

If improperly managed, bacterial fermentations can result in high levels of acetic acid, imparting a vinegar-like sourness. —Joseph V Micallef, Forbes.com, 26 Apr. 2025

The bacterium acetobacter turns the alcohol into acetic acid, which is what makes ACV taste sour.9 ACV shots are made by adding ACV to a small amount of liquid, such as juice or water. —Heather Jones, Verywell Health, 15 Apr. 2025

Celanese shares have suffered a nearly 24% decline this year as the price of methanol — a substantial input cost in acetic acid prices — has been spiking for about 18 months due to global supply shortages. —Pia Singh, CNBC, 14 May 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