[byoo-til, byoot-l]

adjective Chemistry.

containing a butyl group.

Origin of butyl

First recorded in 1865–70; but(yric) + -yl


[byoo-til, byoot-l]


a brand of synthetic rubber prepared by polymerization of butylene containing little butadiene, particularly useful for inner tubes of automobile tires because of its leakproof qualities.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for butyl

Historical Examples of butyl

  • The stuff smelled like a mixture of spirits of ammonia and butyl mercaptan, but it did the job.

    The Highest Treason

    Randall Garrett

  • There are also higher alcohols, that is, those having more complex chemical formulas, such as butyl alcohol.

    Encyclopedia of Diet

    Eugene Christian

  • "And butyl mercaptan; I'm quite aware of that," said the Doctor quickly, to continue the tradition of omniscience.

    Skippy Bedelle

    Owen Johnson

  • It has the characteristic odour of the flowers, and consists of a mixture of butyl and amyl angelates and valerates.

British Dictionary definitions for butyl



(modifier) of, consisting of, or containing any of four isomeric forms of the group C 4 H 9butyl rubber

Word Origin for butyl

C19: from but (yric acid) + -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

Word Origin and History for butyl

hydrocarbon radical, 1868, from butyric acid, a product of fermentation found in rancid butter, from Latin butyrum "butter" (see butter (n.)).

Online Etymology Dictionary, © 2010 Douglas Harper

butyl in Medicine




A hydrocarbon radical, C4H9.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

butyl in Science



The radical C4H9, derived from butane.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.