lepton

IPA/ˈlep.tɒn/
IPA/ˈlep.tɑːn/

lepton — noun

  • leptonsingular
  • leptonsplural

1. in physics, a tiny basic kind of matter, such as an electron or a neutrino, that

1.nounC2
Definition

in physics, a tiny basic kind of matter, such as an electron or a neutrino, that takes part in the weak nuclear force but never in the strong one.

Example

Indra explained that an electron is the most familiar kind of lepton.

definitional frame: 'X is a kind of lepton'

The textbook divides matter into two families: quarks and leptons.

collocation: 'quarks and leptons' as paired categories

Common collocations
  • a charged lepton
  • lepton family
  • lepton number
  • lepton pair
Synonyms
Antonyms
  • quark

    the other main family of elementary matter particles; quarks feel the strong force, leptons do not

Grammar Patterns

a lepton

leptons such as [examples]

Usage Note

Almost exclusively used in physics writing or teaching; rarely heard outside that context. Often appears in the plural 'leptons' when listing categories of matter.

Common Mistakes

A lepton is a small money coin used in Athens.
A lepton is a tiny particle of matter studied in physics.
the physics sense and the currency sense are completely separate; the physics meaning is much more common today.
Protons and neutrons are leptons.
Electrons, muons, and neutrinos are leptons.
protons and neutrons are made of quarks, not leptons.

2. a small unit of older Greek money, worth one hundredth of a drachma, used before

2.nounC2
Definition

a small unit of older Greek money, worth one hundredth of a drachma, used before Greece switched to the euro.

Example

Christopher collected an old Greek lepton from his grandmother's coin box.

noun phrase: 'an old Greek lepton'

In the museum, Tunde held up a worn lepton minted in nineteenth-century Athens.

historical context: 'minted in [place/period]'

Common collocations
  • an old lepton
  • Greek lepton
  • lepta and drachmas

Grammar Patterns

a lepton

[number] lepta

Usage Note

Now historical; you encounter this word in coin-collecting writing, museum labels, or texts about Greece before 2002. The plural is 'lepta', not 'leptons', for this sense — that helps distinguish it from sense 1 in writing.

Common Mistakes

I paid two leptons for the bread.
I paid two lepta for the bread.
the historical currency plural is 'lepta'; 'leptons' refers to physics particles.

Word family

  • leptonic
    adjectiveC2

Synonym discussion

Sense: noun/1

These four words name the basic building blocks and force-carriers in modern physics. A 'lepton' is a fundamental matter particle that feels the weak force but not the strong force — electrons, muons, and neutrinos are the everyday examples. A 'quark' is the other matter family: quarks feel the strong force and combine into protons and neutrons. A 'boson' is different again — bosons are force-carrying particles (photons carry light, for example), not matter. 'Fermion' is the broadest of the four: it is a category that covers both leptons and quarks, defined by their spin. So a useful way to remember the layout is: every lepton is a fermion, but not every fermion is a lepton (quarks are fermions too); and bosons sit in a separate group from all three.

lepton ↗quarkbosonfermion

Common collocations

Nouns

  • lepton family
  • lepton number
  • lepton pair
  • charged lepton

Phrases

  • leptons and quarks

Prepositions

  • a lepton in [a field/family]

Etymology

GreekEnglish

Borrowed into English from Greek 'leptos', meaning 'small' or 'thin'. The Greek coin sense came first in English, since 'lepton' was the name of a tiny copper coin in ancient and modern Greece — literally 'the small one'. Physicists adopted the same word in the 1940s for the new family of light, low-mass particles they were starting to study, again with the idea of 'small'. The two senses share a root but reached English by different routes and at different times.