ac·​ti·​no·​ura·​ni·​um | \ ¦ak-tə-(ˌ)nō-yu̇-ˈrā-nē-əm\

Definition of actinouranium 

: the uranium isotope of mass 235

Love words?

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:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

First Known Use of actinouranium

1918, in the meaning defined above

History and Etymology for actinouranium

International Scientific Vocabulary actino- (from New Latin actinium) + uranium

Keep scrolling for more

Learn More about actinouranium

Share actinouranium

Statistics for actinouranium

Look-up Popularity

Time Traveler for actinouranium

The first known use of actinouranium was in 1918

See more words from the same year

Comments on actinouranium

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


marked by shyness and lack of polish

Get Word of the Day daily email!

Test Your Vocabulary

Liar, Liar Quiz

  • alt-5761dbe2ba986
  • Someone who pretends to be sick in order to avoid work is a:
Name That Thing

Test your visual vocabulary with our 10-question challenge!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

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