Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

Medical Dictionary

thyroid hormone

noun

Medical Definition of thyroid hormone

  1. :  any of several closely related metabolically active compounds (as triiodothyronine) that are stored in the thyroid gland in the form of thyroglobulin or circulate in the blood usually bound to plasma proteins; especially :  thyroxine

Explore M-W

supreme-court-at-dusk
Trending: SCOTUS: 'Bona Fide' relationships
alt-5949565fc7d94
'Negging' Moves Beyond The Bar
istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
June 2017 Words of the Day Quiz
image599301899
Pretty in 'Pink'

Seen and Heard

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

show hide

Love words? Need even more definitions?

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

WORD OF THE DAY

tristful

play

sad or melancholy

Get Word of the Day daily email!

TRENDING NOW

  1. bona fide Made in good faith

  2. surrogate mother From TMZ to the dictionary.

  3. zealot A fanatical partisan

  4. stonewall to be uncooperative, obstructive, or evasive

  5. scurrilous Containing obscenities, abuse, or slander

SEE ALL

Love words? Need even more definitions?

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

Words at Play

alt-5949565fc7d94
'Negging' Moves Beyond The Bar

Not just for pick-up artists anymore

alt-5947fc40f1b5c
In Tech, What Does 'K' Mean?

A buzzword with a long history.

alt-5951697e1a410
When To Use 'Specious' vs. 'Spurious'

These similar words are not interchangeable

alt-594bf2ec5f26e
Quick: Read This!

'Quick' once had a very different meaning

Ask the Editors

decimate-video
Is it wrong to use 'decimate' to mean 'destroy'?

Language changes

serial-comma
The Serial Comma

Why don't they call it the Merriam-Webster comma?

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

istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
June 2017 Words of the Day Quiz

Summer's first WOTD quiz.

Take the quiz
alt-5941ad7527c3c
Yearbook Superlatives Quiz

Is that your picture under "Largest Vocabulary"?

Take the quiz
How Strong Is Your Vocabulary?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Take the quiz
SCRABBLE® Sprint
SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game