Gain access to thousands of additional definitions and advanced search features—ad free! JOIN NOW
: a pale brown pigment in eggshells (as of the domestic hen)
You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.
Start your free trial today and get unlimited access to America's largest dictionary, with:
International Scientific Vocabulary o- + porphyrin
Keep scrolling for more
Resources for ooporphyrin
Comments on ooporphyrin
What made you want to look up ooporphyrin? Please tell us where you read or heard it (including the quote, if possible).
a trusted follower
Get Word of the Day daily email!
Difficult Vocab Quiz
Can you spell these 10 commonly misspelled words?
Test Your Knowledge - and learn some interesting things along the way.
Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!
Semantic bleaching and the power to amaze
Cans of worms, wild-goose chases, and more
Words from the week of 11/16/2018
This is just to say / Don't confuse them
And is one way more correct than the others?
The story of an imaginary word that managed to sneak past our editors and enter the dictionary.
How to use a word that (literally) drives some people nuts.
The awkward case of 'his or her'
Another round of challenging vocab!
(Secret October WOTD Quiz)
A game of winding words.