DictionaryAI

reduce

verb
ri-DOOS/ɹɪˈd(j)us/UKri-JOOS/ɹɪˈd͡ʒuːs/

Formsreduces, reducing, reduced

19 meanings of reduce

Practice

  1. 1
    make lessverbtransitive
    To bring down the size, quantity, quality, value, or intensity of something.

    The new policy aims to reduce traffic in the city center.

    Cutting back on sugar reduced her risk of diabetes.

    UsageUse by for the amount and to for the new level: reduce costs by 10 percent, reduce speed to 20 mph.

    Similardecrease, lower, cut, lessen, diminish

    Oppositeincrease, raise, boost, expand

  2. 2
    simplifyverbtransitive
    To turn something into a simpler or more elementary form, or to treat it as amounting to no more than a single thing, typically followed by "to".

    It is a mistake to reduce every political argument to a question of money.

    Critics accused the film of reducing a complicated war to a simple tale of heroes and villains.

    UsageOften critical: to reduce a complex issue to one cause suggests leaving out what matters.

    Similarsimplify

    Note

    The Latin behind it means to lead back, and this sense keeps the picture: something is led back to what it comes down to. That can be neutral, as in reducing a story to a few sentences. When it means treating something as nothing more than one thing, it is usually a complaint: to reduce a war to heroes and villains is to leave out what matters. Critics call that kind of thinking reductive.

    Checked 5 Nov 2026 · 1 fact

    • Reduce derives from Latin elements meaning ‘back’ and ‘lead’. en.wiktionary.org
  3. 3
    boil downverbtransitive or intransitive
    To thicken a sauce or liquid by boiling off much of its water content.

    Reduce the stock by half before adding the cream.

    The chef reduced the broth to intensify its flavor.

    UsageBy gives the amount lost and to the result: reduce the stock by half, reduce it to a syrup.

    Similarthicken, concentrate

    Oppositedilute

    Note

    A kitchen instruction that names the result as well as the method: reduce the stock by half, or reduce a soup to a slightly thick sauce, as Edward Behr and James MacGuire's The Art of Eating Cookbook (2011) puts it. Boiling off water concentrates flavor and thickens texture.

  4. 4
    chemistryverbtransitive
    To cause a substance to gain electrons or hydrogen, or to lose oxygen, in a chemical reaction.

    Strong agents like lithium aluminum hydride reduce ketones to alcohols.

    In photosynthesis, plants use energy from sunlight to reduce carbon dioxide to sugars.

    Oppositeoxidize

    Note

    Chemistry's half of a pair: whatever is reduced gains electrons, and something else in the same reaction loses them and is oxidized. The three tests in the definition (electrons in, hydrogen in, oxygen out) are different views of one change, a drop in oxidation state. The usual pattern is reduce A to B, as when formaldehyde is reduced to methanol.

    Checked 5 Nov 2026 · 4 facts

    • Reduction involves gaining electrons, while oxidation involves losing them; the processes are paired. chem.uiuc.edu
    • Hydrogen gain and oxygen loss describe chemical reduction. openstax.org
    • Reduction lowers oxidation state. chem.uiuc.edu
    • Formaldehyde can be reduced to methanol. journal.bcrec.id

Practice

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Origin

From Middle English reducen, borrowed through Old French reduire from Latin redūcō, built from re- ("back") plus dūcō ("lead").

Checked 5 Nov 2026 · 2 facts

  • Reduce comes from Middle English reducen through Old French reduire from Latin redūcō. en.wiktionary.org
  • Latin redūcō combines re-, meaning back, and dūcō, meaning lead. en.wiktionary.org