名詞 pion:

1. a meson involved in holding the nucleus together; produced as the result of high-energy particle collision
   同義詞：pi-meson

pi.on

n.Physics （名詞）【物理學(xué)】
A semistable meson produced either in a neutral form with a mass 2'4 times that of an electron and a mean lifetime of 8.4 × 0-7 second or in a positively charged form with a mass 273 times that of an electron and a mean lifetime of 2.' × 0 -8 second. Also called pi meson See table at subatomic particle
π介子：一種半穩(wěn)定介子，或者以一種質(zhì)量比電子重2'4倍的中性形式生成，其平均壽命期為8.4×0-7秒；或者以一種質(zhì)量比電子重273倍的正電極形式生成，其平均壽命期為2.'×0 -8秒 也作 pi meson參見 subatomic particle

來源：
Contraction of pi meson
pi meson的縮寫