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

Plus, jojoba esters in the formula help to nourish lashes from root to tip. —Conçetta Ciarlo, Vogue, 14 Feb. 2025

Likewise, Jamaican rums, known for their pot still production and high ester content, have gained popularity among enthusiasts. —Joseph V Micallef, Forbes, 11 Jan. 2025

On the other hand, there is also a group of retinyl esters that are gentler on the skin, but less effective. —Sarah Han, Allure, 7 Jan. 2025

Key Ingredients: Peptides, alpha lipoic acid, vitamin B3, vitamin C ester, SPF 25 How to Apply: Use the cream as part of a daily, morning-skincare regime. —Kiana Murden, Vogue, 20 Jan. 2025

Word History

Etymology

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

First Known Use

circa 1852, in the meaning defined above

Rhymes for ester

• esther
• fester
• jester
• nester
• nestor
• pester
• prester
• quaestor
• tester
• wester
• yester
• ancestor

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