ester

noun

es·​ter ˈe-stər 

: any of a class of often fragrant organic compounds that can be represented by the formula RCOOR′ and that are usually formed by the reaction between an acid and an alcohol with elimination of water

Examples of ester in a Sentence

Recent Examples on the Web

Cannabis offers a broad spectrum of unique flavors and aromas, all derived from terpenes, esters, and other flavorants. —Chelsea Davis, Forbes, 18 Dec. 2024

New approaches replace the mineral oil with natural esters to allow the interior of the transformer to safely reach higher temperatures, prolonging the device’s lifespan in the process. —IEEE Spectrum, 11 Dec. 2024

Infused with fatty acids and olive oil esters, this formula nourishes your lashes from the root. —Alyssa Brascia, People.com, 23 Nov. 2024

Formulated with niacinamide, glycerin, hydrolyzed jojoba esters and sodium hyaluronate, the toner also calms redness and breakouts, plus strengthens the skin barrier. —Celia Shatzman, Forbes, 26 Nov. 2024

Word History

Etymology

German, from Essigäther ethyl acetate, from Essig vinegar + Äther ether

First Known Use

circa 1852, in the meaning defined above

Kids Definition

ester

noun

es·​ter ˈes-tər 

: an organic compound formed by the reaction between an acid and an alcohol

Medical Definition

ester

noun

es·​ter ˈes-tər 

: any of a class of often fragrant compounds that can be represented by the formula RCOOR′ and that are usually formed by the reaction between an acid and an alcohol usually with elimination of water