Looking for the meaning or definition of the word meson? Here's what it means.
Noun
(rare outside entomology) The mesial plane dividing the body into similar right and left halves.
Noun
(obsolete) A member of a group of subatomic particles having a mass intermediate between electrons and protons. (The most easily detected mesons fit this definition.)
(now specifically, physics) An elementary particle that is composed of a quark and an antiquark, such as a kaon or pion. (Mesons composed of rarer quarks are much heavier.)