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:
“Riverweed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/riverweed. Accessed 29 Nov. 2022.
Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!
See Definitions and Examples »
Get Word of the Day daily email!
Challenging Words You Should Know
You know what it looks like… but what is it called?
A daily challenge for crossword fanatics.
When each letter can be seen but not heard
Some may be more useful than others.
One L or two?
Look up any year to find out
How to use a word that (literally) drives some pe...
Or both? Or neither?
Editor Emily Brewster clarifies the difference.
An old-fashioned rule we can no longer put up with.
See if you can tell the insults from the complime...
Take the quiz
20 questions to help you score 1600
You know what it looks like… but what is it cal...
Can you outdo past winners of the National Spelli...