pion

noun

pi·​on ˈpī-ˌän How to pronounce pion (audio)
: a meson that is a combination of up and down quarks and antiquarks, that may be positive, negative, or neutral, and that has a mass about 270 times that of the electron
pionic adjective

Examples of pion 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.
They are created when protons and neutrons collide, which generates particles known as pions that then decay into muons. IEEE Spectrum, 3 Dec. 2024 The pion theory also outlawed precisely the same collisions. Charlie Wood, WIRED, 3 Nov. 2024 This meddling is what allows the kaon to produce a pion and two neutrinos, the process NA62 seeks. Clara Moskowitz, Scientific American, 1 Oct. 2024 Any leakage is carried by the color-neutral pion and kindred mesons. Aaron Shattuck, Scientific American, 17 Sep. 2024 Above, the top picture (from a later experiment) shows an example of the antiproton (the pale blue streak) annihilating a proton and creating positive and negative particles known as pions (respectively, the red and green lines). Discover Magazine, 1 Sep. 2010 Beams of energy collide with atoms in Earth’s upper atmosphere, spawning charged subatomic particles like pions, muons, electrons, and positrons, whose ionized trails show up as spindly lines in cloud chambers. Bill Gourgey, Popular Science, 23 Nov. 2023 Instead, at these scales, a new effective force emerges—the strong nuclear force, transmitted between nucleons by the exchange of pions. WIRED, 10 Aug. 2023 The positive pion can interfere with other positive pions caused by other atomic flybys. Stephanie Pappas, Scientific American, 11 Jan. 2023

Word History

Etymology

contraction of pi-meson

First Known Use

1950, in the meaning defined above

Time Traveler
The first known use of pion was in 1950

Dictionary Entries Near pion

Cite this Entry

“Pion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/pion. Accessed 22 Dec. 2024.

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!