radi-
combining form
variants:
or radio-
Definition of radi-
1
: radiant energy : radiation
radioactive radiopaque
2
: radioactive
radioelement
3
: radium : X-rays
radiotherapy
4
: radioactive isotopes especially as produced artificially
radiocarbon
5
: radio
radiotelegraphy
6
: radius bone
radio-ulna
Keep scrolling for more
Test Your Vocabulary
The Exceptions Quiz III
-
- Which of these words does not mean "nonsense"?

Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
Anagram puzzles meet word search.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Words at Play
Ask the Editors
Word Games
Share radi-