meth·​yl·​a·​tion | \ ˌme-thə-ˈlā-shən How to pronounce methylation (audio) \

Definition of methylation

: 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

First Known Use of methylation

1855, in the meaning defined above

Keep scrolling for more

Learn More about methylation

Time Traveler for methylation

Time Traveler

The first known use of methylation was in 1855

See more words from the same year

Statistics for methylation

Cite this Entry

“Methylation.” Dictionary, Merriam-Webster, Accessed 12 Jul. 2020.

Keep scrolling for more

More Definitions for methylation


meth·​yl·​ation | \ ˌmeth-ə-ˈlā-shən How to pronounce methylation (audio) \

Medical Definition of methylation

: introduction of the methyl group into a chemical compound especially : dna methylation

Other Words from methylation

methylate \ ˈmeth-​ə-​ˌlāt How to pronounce methylate (audio) \ transitive verb methylated; methylating

Comments on methylation

What made you want to look up methylation? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

Words for Summer: A Quiz

  • a closeup of a sunflower
  • Which of the following words means “of or relating to summer”?
Spell It

Can you spell these 10 commonly misspelled words?

Syn City

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!