functional group

American  

noun

1. a group of atoms responsible for the characteristic behavior of the class of compounds in which the group occurs, as the hydroxyl group in alcohols.

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functional group British  

noun

1. chem the group of atoms in a compound, such as the hydroxyl group in an alcohol, that determines the chemical behaviour of the compound

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functional group Scientific  

1. An atom or group of atoms that replaces hydrogen in an organic compound. Functional groups define the structure of a family of compounds and determine its properties. The carboxyl and hydroxyl groups are functional groups that define the compounds they are part of as organic acids and alcohols, respectively.

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Etymology

Origin of functional group

First recorded in 1935–40