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 .

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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

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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.

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Etymology

Origin of ester

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

Example Sentences

On the second full day of the Milan-Cortina Games, Czech snowboarder Zuzana Maderova won gold in the women's parallel giant slalom after the shock exit of defending champion Ester Ledecka.

From Barron's • Feb. 8, 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

You see, she drove from Mexico Beach, FL to see us in Mobile, AL, and Mary Ester, FL was along her route, about halfway between us.

From Salon • Mar. 29, 2024

Two days later, Dona Ester Trueba died in the bed of pain where she had spent the final years of her life.

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