lepton1 Syllabification: (lep·ton)Pronunciation: /ˈlepˌtän/Definition of lepton noun (plural lepta /-tə/) a monetary unit of Greece until the introduction of the euro, worth one hundredth of a drachma (used only in calculations). Origin:from Greek lepton, neuter of leptos 'small'lepton in other Oxford dictionaries Definition of lepton in the British & World English dictionary