1 of 2


al·​kyl ˈal-kəl How to pronounce alkyl (audio)
: having a monovalent organic group and especially one CnH2n+1 (such as methyl) derived from an alkane (such as methane)


2 of 2


: a compound of one or more alkyl groups with a metal
mercury alkyls

Examples of alkyl in a Sentence

Recent Examples on the Web
This power is owed in part to its unique structure; the unusually long alkyl side chains of seven carbon atoms give an edge over conventional THC's five-carbon makeup. Amber Smith, Discover Magazine, 24 Feb. 2023 Perfluorinated and polyfluorinated alkyl substances, or PFASs, are considered indestructible chemicals. Lars Fischer, Scientific American, 31 Jan. 2022 The alkyl side chain is the driving force behind a cannabinoid's effects on humans. Kristen Rogers, CNN, 3 Feb. 2020
The second concern, Radić says, is that A-232’s alkyl amine group could enable it to target other enzymes in addition to AChE—and that raises the specter of severe symptoms arising months or years after exposure. Richard Stone, Science | AAAS, 19 Mar. 2018 The alkyl chloride and organophosphate precursors are toxic, but not nearly to the degree of VX, which was developed in the 1950s for chemical warfare and is the most potent of all nerve agents. Ben Otto, WSJ, 6 Oct. 2017 Dragna recommends finding personal care products that contain surfactants from the alkyl polyglycosides instead, the most common of which is decyl glucoside, because the head group is a sugar instead of a sulfate. Ajc Homepage, ajc, 28 Aug. 2017

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'alkyl.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History



probably from German, from Alkohol alcohol

First Known Use


1882, in the meaning defined above


1889, in the meaning defined above

Time Traveler
The first known use of alkyl was in 1882

Dictionary Entries Near alkyl

Cite this Entry

“Alkyl.” Dictionary, Merriam-Webster, Accessed 20 Jul. 2024.

Medical Definition


1 of 2 adjective
al·​kyl ˈal-kəl How to pronounce alkyl (audio)
: of, relating to, or being an alkyl
alkyl mercurials attack the brain cellsL. J. Goldwater


2 of 2 noun
: a monovalent aliphatic radical CnH2n+1 (as methyl)
broadly : a monovalent aliphatic, aromatic-aliphatic, or alicyclic hydrocarbon radical
: a compound of one or more alkyl groups with a metal
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