pion

[pahy-on]

noun Physics.

the first meson to be discovered: it has spin 0 and may be positively or negatively charged or neutral; charged pions decay into a muon and a neutrino or antineutrino. Symbol: π

Origin of pion

First recorded in 1950–55; pi (meson) + -on¹

Also called pi meson.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for pion

Historical Examples of pion

Do not forget next week at the home of Endora, on the Mountain of Pion.
Saronia
Richard Short
I refer to the pion pine, of which there are several species.
North America
Israel C. Russell
But he turned and scrambled up a rocky bank into the pion woods that border the benches of the Meteetsee.
The Biography of a Grizzly
Ernest Seton-Thompson
This heres the Wagon Tire House, returned its proprietor, rising and shaking the pion slivers from her checked apron.
Ainslee's magazine, Volume 16, No. 3, October, 1905
Various
The dense forest consists of pion pine, juniper, Douglas fir, and western yellow pine.
Mesa Verde National Park, Colorado
Anonymous

British Dictionary definitions for pion

pion

pi meson

noun

physics a meson having a positive or negative charge and a rest mass 273.13 times that of the electron, or no charge and a rest mass 264.14 times that of the electron

Word Origin for pion

C20: from Greek letter pi 1 + on

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

Word Origin and History for pion

1951, from Greek letter pi + -on.

pion in Science

pion

[pī′ŏn′]

A meson occurring either in a neutral form with a mass 264 times that of an electron and a mean lifetime of 8.4 X 10-17 seconds or in a positively or negatively charged form with a mass 273 times that of an electron and a mean lifetime of 2.6 X 10-8 seconds. The pion was once believed to be the particle that mediates the strong force, which holds nucleons together in the nucleus; it is now believed that the gluon is the mediator particle. Pions do interact with nucleons, however, and are able to transform neutrons into protons and vice versa. Also called pi-meson See Table at subatomic particle.