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quantum

SayKWON-tuhm/ˈkwɑntəm/UK/ˈkwɒntəm/

Noun pluralquantums, quanta

8 meanings of quantum

Practice

  1. 1
    adjective
    Related to quantum physics or technologies that use it, such as quantum computers.

    She studies quantum physics at college.

    Light behaves in strange ways at the quantum level.

    Oppositeclassical

    Note
  2. 2
    adjectivecolloquial
    Describes a change that is very big and important, often happening all at once instead of slowly.

    The new phone is a quantum leap from the old one.

    Moving to the city was a quantum change in her life.

    UsageSay a quantum leap for a big change.

    Similargiant, dramatic, massive, huge, radical

    Oppositegradual, incremental

    Note
  3. 3
    smallest unitnouncountable or uncountable
    The smallest amount of something, like energy or light, that cannot be split into smaller parts.

    Like coins: you can pay one cent or two cents, but never half a cent.

    A photon is a single quantum of light.

    Hot objects give off energy in tiny quanta.

    UsageMore than one is quanta.

    Note
  4. 4
    computing fieldnoununcountableabbreviationellipsis
    Short for quantum computing. Used in tech talk about computers that run on quantum physics.

    Big tech companies are spending billions on quantum.

    She left her old job to work in quantum.

    UsageSay work in quantum.

  5. 5
    nouncountable or uncountable
    An amount of something, especially how much money a court awards or how heavy a punishment is.

    The judge will decide the quantum of damages next week.

    Farmers want to know the quantum of help they will get after the floods.

    UsageSay the quantum of something.

    Similaramount, extent, quantity, size

    Note

Less common meanings

  1. 6
    noun
    The amount of time a computer gives one thread, a small part of a program, to do its work.
  2. 7
    noun
    In disease models, an amount of germs in the air that gives a person about a two-in-three chance of getting sick.
  3. 8
    noun
    A part of a mathematical space that has a clear mark or edge around it.
    Defined parts of a manifoldness are called Quanta
    1882, William Kingdon Clifford, Mathematical PapersHere, Quanta means marked-off parts of a larger whole.

Practice

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Origin

From Latin quantus, meaning "how much".

Checked 1 Nov 2026 · 2 facts