Definition of positronium
: a short-lived system that consists of a positron and an electron bound together and is suggestive of a hydrogen atom
Test Your Vocabulary
Words Named After People
-
- Namesake of the leotard, Jules Léotard had what profession?

Test your visual vocabulary with our 10-question challenge!
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Share positronium
Time Traveler for positronium
The first known use of positronium was in 1945
See more words from the same year