pion

[ pahy-on ]

/ ˈpaɪ ɒn /

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

Nearby words

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. 2019

Examples from the Web for pion

By-and-by they came to a marvelous cave in the Hill of Pion and entered into it and feasted, and presently they hurried on again.
The Innocents Abroad|Mark Twain (Samuel Clemens)
The girl found Antonio propped against a pion tree, solacing himself philosophically with cigarettes.
Brand Blotters|William MacLeod Raine
The dense forest consists of pion pine, juniper, Douglas fir, and western yellow pine.
Mesa Verde National Park, Colorado|Anonymous
Both the pion and the camass are largely utilized even at the present day for food by the Indians.
North America|Israel C. Russell

They found Suzanne and Arabella industriously carrying in aprons full of pion chips for the kitchen stove.
Heart's Desire|Emerson Hough

British Dictionary definitions for pion

pion

pi meson

/ (ˈpaɪɒn) /

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

pion

1951, from Greek letter pi + -on.

Science definitions for pion

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.