methylation

noun

meth·​yl·​a·​tion ˌme-thə-ˈlā-shən How to pronounce methylation (audio)
: the introduction of a methyl radical into a substance
The methylation of metals (that is, the substitution of a metal atom for the hydrogen atom of the hydroxyl group of a methyl alcohol molecule) can result in the metal's becoming volatile.—Corale L. Brierley
especially : dna methylation
As cells begin to specialize into adult tissues, methylation seems to inactivate genes that are no longer needed. —John Travis

Examples of methylation in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The body normally keeps LINE1 quiet through DNA methylation, chemical tags that silence the sequence. — Hanna Wickes, Charlotte Observer, 17 Oct. 2026 Follow-up research from the Dog Aging Project extending the LINE1 methylation findings beyond the initial 864-dog cohort. — Hanna Wickes, Kansas City Star, 16 Oct. 2026 The study drew on 864 dogs enrolled in the nationwide Dog Aging Project and found that larger dogs lose 35% more LINE1 methylation than smaller ones. — Hanna Wickes, Miami Herald, 16 Oct. 2026 Think of methylation as a chemical lid that keeps LINE1 quiet. — Hanna Wickes, Fort Worth Star-Telegram, 16 Oct. 2026 See All Example Sentences for methylation

Word History

First Known Use

1855, in the meaning defined above

Time Traveler
The first known use of methylation was in 1855

Phrases Containing methylation

Rhymes for methylation

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Browse Nearby Words

methylate
methylation
methyl bromide
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Cite this Entry

“Methylation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/methylation. Accessed 20 Oct. 2026.

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Medical Definition

methylation

noun
meth·​yl·​ation ˌmeth-ə-ˈlā-shən How to pronounce methylation (audio)
: introduction of the methyl group into a chemical compound
especially : dna methylation
methylate
ˈmeth-ə-ˌlāt How to pronounce methylation (audio)
transitive verb
methylated; methylating
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