SINCE 1828

An Encyclopædia Britannica Company

Medical Dictionary

trimethyl

play

adjective tri·meth·yl \(ˈ)trī-ˈmeth-^əl, British also -ˈmē-ˌthīl\

Medical Definition of trimethyl

: containing three methyl groups in a molecule

Seen and Heard

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

show

WORD OF THE DAY

perfunctory

play

done merely as a duty

Words at Play

alt-599492594f435

How 'Wonderful' Lost Its Sense of Wonder

A case of semantic bleaching

dog-covering-face

Don't Let Reading This Be Another 'Coulda' 'Shoulda' 'Woulda'

PSA: They're three separate words.

Food Words for Strong Flavors

A tasting menu of vivid flavor descriptions

alt-5993066a3afad

What's the Plural of 'Maitre d''?

Use this word to confuse a French speaker.

Ask the Editors

video-title-words-of-the-year-1066

Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless

Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals

Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

time-traveler-quiz-which-word-came-first

Time Traveler Quiz: Which Word Came First?

Which word entered the English language first?

Take the quiz

Name More Food!

Test your knowledge of food vocabulary!

Take the quiz

True or False?

Test your knowledge - and maybe learn something along the way.

Take the quiz

SCRABBLE® Sprint

SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game