Noun
preon (plural preons)
(physics) A hypothetical point-like particle, supposed to be a subcomponent of quarks and leptons and possibly bosons too.
In essence, preon theory tries to do for the Standard Model what the Standard Model did for the particle zoo that came before it. Source: Internet
Preon theory main According to preon theory there are one or more orders of particles more fundamental than those (or most of those) found in the Standard Model. Source: Internet