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noun (1)

lep·​ton lep-ˈtän How to pronounce lepton (audio)
plural lepta lep-ˈtä How to pronounce lepton (audio)
: a former monetary unit equal to ¹/₁₀₀ drachma


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noun (2)

lep·​ton ˈlep-ˌtän How to pronounce lepton (audio)
: 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 adjective

Examples of lepton in a Sentence

Recent Examples on the Web
Their efforts have led to the Standard Model of particle physics, which describes the most fundamental ingredients of matter (leptons and quarks) and the forces that control them (the electromagnetic, strong and weak forces). Daniel Garisto, Scientific American, 13 Dec. 2023 Another possibility is a new type of particle called a leptoquark—a strange kind of boson that shares properties with quarks as well as leptons such as the muon. Marcela Carena, Scientific American, 1 Oct. 2021 Fermions make up all the matter in the Universe and include leptons and quarks. Jennifer Ouellette, Ars Technica, 24 Mar. 2023 The more exotic possibility is that LHCb researchers are detecting hints of a fabled particle — the leptoquark — that can turn a quark into a lepton and vice versa. Quanta Magazine, 26 May 2020

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'lepton.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Time Traveler
The first known use of lepton was circa 1741

Dictionary Entries Near lepton

Cite this Entry

“Lepton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lepton. Accessed 28 Feb. 2024.

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