Meson
WordNet
noun
(1) An elementary particle responsible for the forces in the atomic nucleus; a hadron with a baryon number of 0
WiktionaryText
Noun
- The mesial plane dividing the body into similar right and left halves.
Noun
- A member of a group of subatomic particles having a mass intermediate between electrons and protons. (The most easily detected mesons fit this definition.)
- An elementary particle that is composed of a quark and an antiquark, such as a kaon or pion. (Meson composed of rarer quarks are much heavier.)