i Register
In some senses, meson is marked as obsolete. Watch for register when choosing this word.
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. (Mesons composed of rarer quarks are much heavier.)