Definition of "positronium" []

• A short-lived association of an electron and a positron bound together in a configuration resembling the hydrogen atom. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "But stabilize the matter-antimatter mix into a substance called positronium — as a couple of UC Riverside physicists did for a record-breaking 100 nanoseconds — and you're on your way to turning that jolt into a focused, ultrapowerful laser."
• "(If you are willing to postulate a matter-antimatter explosive, aka a positronium bomb, then P can increase by the maximal amount from 0 to e/3.)"
• "Also, di-positronium is made from electrons and positrons which are hardly "ordinary" and can annihilate itself; no need to stick in extra positrons..."