lactic acid

noun

: a hygroscopic organic acid C₃H₆O₃ present normally especially in muscle tissue as a by-product of anaerobic glycolysis, produced in carbohydrate matter usually by bacterial fermentation, and used especially in food and medicine and in industry

Examples of lactic acid in a Sentence

Recent Examples on the Web

The cleanser and the exfoliator contained lactic acid, followed by exfoliating acid. —Larry Stansbury, Essence, 22 July 2025

What other body traits attract mosquitoes? Body odor and sweat Mosquitoes are highly sensitive to body odor, particularly to compounds like lactic acid, ammonia and uric acid found in sweat, according to a post by Our Blood Institute. —Brandi D. Addison, Austin American Statesman, 21 July 2025

Cyclists have used sodium bicarbonate for years to boost performance by helping mitigate the effects of lactic acid, making the legs feel less painful, but a historic issue has been stomach issues and slow absorption rates. —Jacob Whitehead, New York Times, 12 July 2025

Ingredients like buttermilk or yogurt flavor and tenderize meat through lactic acid. —Katie Rosenhouse, Southern Living, 22 June 2025

Word History

First Known Use

1790, in the meaning defined above

Rhymes for lactic acid

• antacid
• placid

Kids Definition

lactic acid

noun

lac·​tic acid

ˌlak-tik-

: an organic acid present especially in muscle tissue as a result of the breakdown of carbohydrates (as glycogen), is made from carbohydrates usually by fermentation by bacteria, and is used especially in food and medicine

Medical Definition

lactic acid

noun

: a hygroscopic organic acid C₃H₆O₃ that is known in three optically isomeric forms:

a

or D-lactic acid

ˈdē- 

: the dextrorotatory form present normally in blood and muscle tissue as a product of the anaerobic metabolism of glucose and glycogen

b

or L-lactic acid

ˈel- 

: the levorotatory form obtained by biological fermentation of sucrose

c

or DL-lactic acid

ˈdē-ˈel- 

: the racemic form present in food products and made usually by bacterial fermentation (as of whey or raw sugar) but also synthetically, and used chiefly in foods and beverages, in medicine, in tanning and dyeing, and in making esters for use as solvents and plasticizers