ester

American  

[es-ter] / ˈɛs tər /

noun

Chemistry.

1. a compound produced by the reaction between an acid and an alcohol with the elimination of a molecule of water, as ethyl acetate, C 4 H 8 O 2 , or dimethyl sulfate, C 2 H 6 SO 4 .

---

ester British  

/ ˈɛstə /

noun

1. chem any of a class of compounds produced by reaction between acids and alcohols with the elimination of water. Esters with low molecular weights, such as ethyl acetate, are usually volatile fragrant liquids; fats are solid esters

---

ester Scientific  

/ ĕs′tər /

1. An organic compound formed when an acid and an alcohol combine and release water. Esters formed from carboxylic acids are the most common, and have the general formula RCOOR|||PRIMARY_STRESS|||, where R and R|||PRIMARY_STRESS||| are organic radicals. Esters formed from simple hydrocarbon groups are colorless, volatile liquids with pleasant aromas and create the fragrances and flavors of many flowers and fruits. They are also used as food flavorings. Larger esters, formed from long-chain carboxylic acids, commonly occur as animal and vegetable fats, oils, and waxes. Esters have a wide range of uses in industry.

---

Etymology

Origin of ester

First recorded in 1850–55; coined by L. Gmelin (1788–1853), German chemist

Example Sentences

Ester Ledecka, from the Czech Republic, and Austria's Anna Gasser both blew their chances of becoming the first snowboarders in Olympic history to win three titles in a row earlier in the Milan-Cortina Games.

From Barron's • Feb. 11, 2026

Czech superstar Ester Ledecka takes aim at an unprecedented third consecutive Olympic gold in the women's parallel giant slalom.

From BBC • Feb. 2, 2026

New survey data released by Ester Fuchs in October showed that 29% of families with young children in New York City found child care unaffordable, with wide disparities among neighborhoods.

From The Wall Street Journal • Nov. 5, 2025

“People were reluctant to leave because they had faith in the system,” said Ester Song, 35.

From Los Angeles Times • Jan. 20, 2025

There was a great commotion in the house, because there was going to be a party in Tres Marias for the first time since the forgotten days when Dona Ester was a girl.

From "The House of the Spirits: A Novel" by Isabel Allende