Definition of nonbaryonic
: not being, relating to, or consisting of baryons : not baryonic The only restriction on the identity of the dark matter is that it is nonbaryonic. In this context, that means mainly that the matter is not composed of neutrons or protons; it has to be some particle that does not take part in the structure of ordinary atoms and molecules. — Dietrick E. Thomsen
First Known Use of nonbaryonic
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