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

Shades: 30 Key ingredients: Mica, glycerin, sodium hyaluronate, titanium dioxide (SPF), silica, orange peel oil, jojoba esters, vitamin E Size: 1 fl oz. —Kiana Murden, Vogue, 10 Jan. 2025

It’s also got glycerin and jojoba esters to keep skin hydrated. —Venus Wong, refinery29.com, 20 Dec. 2024

Infused with pearl pigments, glossy ester, and mica, the hues give off a diamond-like shine. —Jenny Berg, Vogue, 21 Dec. 2024

This seasonal beer is golden in color with a big floral aroma, mild ginger spice flavor, and Belgian yeast esters of fruit and bubblegum. —Kathryn Gregory, The Courier-Journal, 9 Dec. 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