Why was "tantrum" trending last week?


[myoo-oh-nee-uh m] /myuˈoʊ ni əm/
noun, Physics.
an electron and a positively charged muon bound together by electrical attraction in the same manner as the electron and proton in a hydrogen atom.
1955-60; mu(on) + -onium, probably extracted from positronium Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
Examples from the web for muonium
  • He was conducting a laser experiment used to measure the energy levels of muonium, an atom consisting of a muon and an electron.
  • Helium gas is used to inhibit muonium formation by positive muons.
Encyclopedia Article for muonium

short-lived quasi-atom composed of a positive muon (an antiparticle), as nucleus, and an ordinary negative electron. It is formed when a positive muon captures an atomic electron after being slowed down in matter. Muoniums form a few compounds with gases such as nitrogen dioxide and ethylene. Muonium research throws some light on the puzzling nature of muons (essentially heavy electrons) and their relation to ordinary electrons.

Learn more about muonium with a free trial on
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source

Word of the Day

Difficulty index for muonium

Few English speakers likely know this word

Word Value for muonium

Scrabble Words With Friends

Nearby words for muonium