lepton
1 of 2noun (1)
lep·ton lep-ˈtän 
plural lepta lep-ˈtä
: a former monetary unit equal to ¹/₁₀₀ drachma
lepton
2 of 2noun (2)
lep·ton ˈlep-ˌtän
: any of a family of particles (such as electrons, muons, and neutrinos) that have spin quantum number ¹/₂ and that experience no strong forces
leptonic
lep-ˈtä-nik
adjective 
Word History
Etymology
Noun (1)
Modern Greek, from Greek, a small coin, from neuter of leptos peeled, slender, small, from lepein to peel — more at leper
Noun (2)
Greek leptos + English -on entry 2
First Known Use
Noun (1)
circa 1741, in the meaning defined above
Noun (2)
circa 1929, in the meaning defined above