• synonyms


[al-kuh l]Chemistry
  1. containing an alkyl group.
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  1. an alkyl group.
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Origin of alkyl

1880–85; < German, equivalent to Alk(ohol) alcohol + -yl -yl
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for alkyl

Historical Examples

  • Hydrogen may be substituted in these chains by alkyl or aromatic groups.

    Animal Proteins

    Hugh Garner Bennett

  • The glyoxalines are basic in character, and the imide hydrogen is replaceable by metals and alkyl groups.

  • For instance, an alkyl may be substituted for the hydroxyl hydrogen in an alcohol molecule, when an ether results.

  • The influence of position of an alkyl in the aromatic bodies is well shown in ortho-, para- and meta-derivatives.

  • We may also notice that thio-ethers combine with alkyl iodides to form sulphine or sulphonium compounds, R3SI.

British Dictionary definitions for alkyl


  1. (modifier) of, consisting of, or containing the monovalent group C n H 2 n +1alkyl group or radical
  2. an organometallic compound, such as tetraethyl lead, containing an alkyl group bound to a metal atom
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Word Origin

C19: from German, from Alk (ohol) alcohol + -yl
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

alkyl in Medicine


  1. A monovalent radical, such as ethyl or propyl, having the general formula CnH2n+1.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

alkyl in Science


  1. A radical that has the general formula CnH2n+1, formed by removing a hydrogen atom from an alkane. Ethyl and propyl are alkyls.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.