'lepton' definitions:

Definition of 'lepton'

From: WordNet
noun
100 lepta equal 1 drachma in Greece
noun
An elementary particle that participates in weak interactions; has a baryon number of 0

Definition of 'lepton'

From: GCIDE
  • lepton \lepton\ n. (Physics) an elementary particle that participates in weak interactions but does not participate in the strong interaction; it has a baryon number of 0. Some known leptons are the electron, the negative muon, the tau-minus particle, and the neutrinos associated with each of these particles. [WordNet 1.5 +PJC]