International Scientific Vocabulary hepta- + oxide
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:
Cite this Entry
“Heptoxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/heptoxide. Accessed 7 Oct. 2022.
See Definitions and Examples »
Get Word of the Day daily email!
Challenging Words You Should Know
Test your knowledge - and maybe learn something along the way.
A daily challenge for crossword fanatics.
Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!
As illustrated by some very smart pups
Bikini, bourbon, and badminton were places first
Do you take pride in Pride?
Look up any year to find out
How to use a word that (literally) drives some pe...
We're intent on clearing it up
Editor Emily Brewster clarifies the difference.
"The public is a hot mess"
Test your visual vocabulary!
Take the quiz
Level up your vocabulary with these newly added w...
Test your knowledge - and maybe learn something a...
Can you outdo past winners of the National Spelli...