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positronium

American

[poz-i-troh-nee-uhm] / ˌpɒz ɪˈtroʊ ni əm /

noun

Physics.

a short-lived atomic system consisting of a positron and an electron bound together.

positronium British

/ ˌpɒzɪˈtrəʊnɪəm /

noun

physics a short-lived entity consisting of a positron and an electron bound together. It decays by annihilation to produce two or three photons

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of positronium

First recorded in 1945; positron + -ium; coined by Arthur E. Ruark (1899–1979), U.S. physicist

Example Sentences

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See Examples For:

positronium

Dr. Yasuyuki Nagashima is a Professor in the Department of Physics at Tokyo University of Science, Japan, specializing in positron and positronium physics.

From Science Daily ● Apr. 28, 2026

They successfully demonstrated matter-wave diffraction in a beam of positronium.

From Science Daily ● Apr. 28, 2026

Dr. Yugo Nagata is an Associate Professor in the Department of Physics at Tokyo University of Science, Japan, specializing in positronium and atomic physics.

From Science Daily ● Apr. 28, 2026

In addition to confirming its quantum properties, positronium diffraction could lead to practical applications.

From Science Daily ● Apr. 28, 2026

One of the first experiments frozen positronium could be used for is to see if its antimatter part follows Einstein's Theory of General Relativity in the same way as the matter part.

From BBC ● Feb. 22, 2024

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023