T4

noun

ˈtē-ˈfȯr How to pronounce T4 (audio)
variants or T4
: thyroxine

Word History

Etymology

probably from thyronine, the amino acid of which thyroxine is a derivative + 4, the number of iodine atoms it contains

First Known Use

1974, in the meaning defined above

Time Traveler
The first known use of T4 was in 1974

Dictionary Entries Near T4

T3

T4

T4 cell

See More Nearby Entries 

Cite this Entry

“T4.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/T4. Accessed 23 Dec. 2024.

Copy Citation

Share

Medical Definition

T4

noun
variants or T4
ˈtē-ˈfō(ə)r
: thyroxine

More from Merriam-Webster on T4

Britannica.com: Encyclopedia article about T4

Love words? Need even more definitions?

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

Popular in Grammar & Usage

See All

Point of View: It's Personal

Plural and Possessive Names: A Guide

What's the difference between 'fascism' and 'socialism'?

More Commonly Misspelled Words

Words You Always Have to Look Up
See All

Popular in Wordplay

See All

8 Words with Fascinating Histories

8 Words for Lesser-Known Musical Instruments

Birds Say the Darndest Things

10 Words from Taylor Swift Songs (Merriam's Version)

10 Scrabble Words Without Any Vowels
See All

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
naughty or nice
Are you naughty or nice? Quiz He's making a quiz, and checking it twice...