lactone

American

[lak-tohn] / ˈlæk toʊn /

noun

Chemistry.

any of a group of internal esters derived from hydroxy acids.

lactone British

/ ˈlæktəʊn, lækˈtɒnɪk /

noun

any of a class of organic compounds formed from hydroxy acids and containing the group -C(CO)OC-, where the carbon atoms are part of a ring

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

lactone Scientific

/ lăk′tōn′ /

Any of various organic esters derived from organic acids by removal of water. Lactones are formed when the carboxyl (COOH) group of the acid reacts with a hydroxyl (OH) group in the same acid, releasing water and causing the carbon atom to join to the hydroxyl's remaining oxygen atom, forming a ring. Vitamin C, the antibiotic erythromycin, and many commercially important substances are lactones.

Other Word Forms

Derived Forms

lactonic

adjective

Etymology

Origin of lactone

First recorded in 1840–50; lact- + -one

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In a recent paper in the Journal of the American Chemical Society, researchers from the Monash Warwick Alliance Combatting Emerging Superbug Threats Initiative reported the discovery of a potent new antibiotic called pre-methylenomycin C lactone.

From Science Daily • Oct. 29, 2025

Encouragingly, the research team found no evidence of bacterial resistance to pre-methylenomycin C lactone in Enterococcus under conditions that typically lead to resistance against vancomycin.

From Science Daily • Oct. 29, 2025

Acyl-homoserine lactone acylase from Ralstonia strain XJ12B represents a novel and potent class of quorum-quenching enzymes.

From Nature • Nov. 14, 2017

In dogs experimentally infected with two different heartworm isolates taken from suspected lack-of-efficacy cases from the Delta region, the parasites survived repeated treatment with a macrocyclic lactone.

From Nature • Mar. 28, 2017

Solution in dilute alkali was supposed to be accompanied by the rupture of the lactone ring with the formation of the quinonoid salt shown in 2.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" by Various

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023