WordReference Random House Unabridged Dictionary of American English © 2024pi′ me′son, [Physics.]- Physicspion.
Collins Concise English Dictionary © HarperCollins Publishers::
pi meson n - another name for pion
pi•on (pī′on),USA pronunciation n. [Physics.]- Physicsthe 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 Also called pi meson.
- pi (meson) + -on1 1950–55
Collins Concise English Dictionary © HarperCollins Publishers::
pion /ˈpaɪɒn/, pi meson n - 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
Etymology: 20th Century: from Greek letter pi1 + on