Definition of ester in English:



  • An organic compound made by replacing the hydrogen of an acid by an alkyl or other organic group. Many naturally occurring fats and essential oils are esters of fatty acids.

    • ‘Fatty acid methyl esters were analyzed by gas chromatography as described above.’
    • ‘Fatty esters help replace natural esters missing from older, dryer skin types.’
    • ‘The ester ethyl acetate can be produced using either an organic or inorganic acid.’
    • ‘Inside is a solution of an oxalate ester and a fluorescent dye, as well as a smaller glass tube that contains hydrogen peroxide.’
    • ‘Glycerol esters are utilized in cakes, breads and other bakery products as lubricants and softening agents.’


Mid 19th century from German, probably from a blend of Essig ‘vinegar’ and Äther ‘ether’.