positron

noun

pos·​i·​tron ˈpä-zə-ˌträn How to pronounce positron (audio)
: a positively charged particle having the same mass and magnitude of charge as the electron and constituting the antiparticle of the electron

called also antielectron

Examples of positron in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Great balls of glue Enter the BES III experiment, an electron-positron collider specifically designed to study J/ψ particles for telltale glueball signatures. — Jennifer Ouellette, ArsTechnica, 12 Aug. 2026 The main way that happens is by colliding electrons and their antimatter partners, positrons. — Matt Von Hippel, Quanta Magazine, 29 July 2026 Full-body scans use different technologies, including magnetic resonance imaging (MRI), computed tomography (CT) or positron emission tomography (PET), according to the Dana-Farber Cancer Institute. — Melissa Rudy, FOXNews.com, 20 July 2026 The strategy process evaluated a wide range of proposals, including linear electron-positron colliders, muon colliders, electron-proton facilities, and reuse of the existing LHC tunnel. — Florencia Canelli, Scientific American, 1 July 2026 See All Example Sentences for positron

Word History

Etymology

positive + -tron (as in electron)

First Known Use

1933, in the meaning defined above

Time Traveler
The first known use of positron was in 1933

Phrases Containing positron

Rhymes for positron

See All Rhymes for positron

Browse Nearby Words

positrino
positron
positron-emission tomography
See all Nearby Words

Cite this Entry

“Positron.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/positron. Accessed 15 Aug. 2026.

Copy Citation

Kids Definition

positron

noun
pos·​i·​tron ˈpäz-ə-ˌträn How to pronounce positron (audio)
: a positively charged particle having the same mass and size of charge as the electron

Medical Definition

positron

noun
pos·​i·​tron ˈpäz-ə-ˌträn How to pronounce positron (audio)
: a positively charged particle having the same mass and magnitude of charge as the electron and constituting the antiparticle of the electron

called also positive electron

More from Merriam-Webster on positron

Britannica.com: Encyclopedia article about positron

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

7 Pairs of Commonly Confused Words

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?
See More

Popular in Wordplay

See More

Words from the 'Odyssey'

The Longest Long Words List

It's a Scorcher! Words for the Summer Heat

The Words of the Week - Aug. 14

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

A Who’s Who Regarding ‘Who’s’ and ‘Whose’

Words from the 'Odyssey'

The Longest Long Words List
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
image of a green cube out of place in a lineup of red spheres
Odd Word Out: Synonyms Vol. 2 Quiz Figure out which word isn't like the others.
See All