lepton

n. any of a number of subatomic particles that have very little mass

In physics, a lepton is a particle with spin-1/2 (a fermion) that does not experience the strong interaction (that is, the strong nuclear force). The leptons form a family of elementary particles that are distinct from the other known family of fermions, the quarks.
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Noun
1. 100 lepta equal 1 drachma
(hypernym) Greek monetary unit
(part-holonym) drachma, Greek drachma
2. an elementary particle that participates in weak interactions; has a baryon number of 0
(hypernym) elementary particle, fundamental particle, subatomic particle
(hyponym) electron, negatron

n. lepton, any of a number of subatomic particles that have very little mass; an aluminum coin of modern Greece

n. lepton, any of a number of subatomic particles that have very little mass