View synonyms for reduction


[ ri-duhk-shuhn ]


  1. the act of reducing or the state of being reduced.
  2. the amount by which something is reduced or diminished.
  3. a form produced by reducing a copy on a smaller scale.
  4. Cell Biology. meiosis, especially the first meiotic cell division in which the chromosome number is reduced by half.
  5. Chemistry. the process or result of reducing.
  6. Movies. the process of making a print of a narrower gauge from a print of a wider gauge:

    the reduction of 35-millimeter films to 16-millimeter films for the school market.

  7. a village or settlement of Indians in South America established and governed by Spanish Jesuit missionaries.


/ rɪˈdʌkʃən /


  1. the act or process or an instance of reducing
  2. the state or condition of being reduced
  3. the amount by which something is reduced
  4. a form of an original resulting from a reducing process, such as a copy on a smaller scale
  5. a simplified form, such as an orchestral score arranged for piano
  6. maths
    1. the process of converting a fraction into its decimal form
    2. the process of dividing out the common factors in the numerator and denominator of a fraction; cancellation


/ rĭ-dŭkshən /

  1. The changing of a fraction into a simpler form, especially by dividing the numerator and denominator by a common factor. For example, the fraction 8 12 can be reduced to 4 6 , which can be further reduced to 2 3 , in each case by dividing both the numerator and denominator by 2.
  2. A chemical reaction in which an atom or ion gains electrons, thus undergoing a decrease in valence. If an iron atom having a valence of +3 gains an electron, the valence decreases to +2.
  3. Compare oxidation


  1. Any chemical reaction in which the atoms in a material take on electrons .

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Reduction is the opposite of oxidation .
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Derived Forms

  • reˈductive, adjective
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Other Words From

  • re·duction·al adjective
  • anti·re·duction adjective
  • nonre·duction noun
  • nonre·duction·al adjective
  • over·re·duction noun
  • prore·duction adjective
  • self-re·duction noun
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Word History and Origins

Origin of reduction1

First recorded in 1475–85; earlier reduccion, from Middle French reduction, from Latin reductiōn- (stem of reductiō ) “a bringing back,” equivalent to reduct(us) (past participle of redūcere “to lead back” ) + -iōn- noun suffix; reduce, -ion
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Beginning students of chemistry are understandably puzzled by the term reduction : shouldn't a reduced atom or ion be one that loses electrons rather than gains them? The reason for the apparent contradiction comes from the early days of chemistry, where reduction and its counterpart, oxidation, were terms invented to describe reactions in which one substance lost an oxygen atom and the other substance gained it. In a reaction such as that between two molecules of hydrogen (2H 2 ) and one of oxygen (O 2 ) combining to produce two molecules of water (2H 2 O), the hydrogen atoms have gained oxygen atoms and were said to have become “oxidized,” while the oxygen atoms have (as it were) lost them by attaching themselves to the hydrogens, and were said to have become “reduced.” Importantly, though, in the process of gaining an oxygen atom, the hydrogen atoms have had to give up their electrons and share them with the oxygen atoms, while the oxygen atoms have gained electrons. Thus comes the apparent paradox that the “reduced” oxygen has in fact gained something, namely electrons. Today the terms oxidation and reduction are used of any reaction, not just one involving oxygen, where electrons are (respectively) lost or gained.
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Example Sentences

Sure enough, the average change in diastolic blood pressure was a clinically significant reduction of five mmHg, which is good news.

Driven by environmental concerns, Kim-Parker saw an opportunity to create a space that would aid in the reduction of pollution in the fashion landscape.

From Fortune

Those reductions would mean much longer wait times and more crowded buses and subways.

From Fortune

The potential for future reductions in the cost of electricity from silicon solar, for example, is limited.

The housing authority agreed to lower Brown’s rent to $318 a month but said the reduction would not take effect until March.

Does that mean a reduction in policing would be a good thing?

Like many I spoke to, Williams seemed to desire a reorientation of policing, rather than just a reduction.

Proper use could lead to weight loss and reduction in gastric reflux.

The reduction in the unemployment levels is largely due to part time jobs and more people simply giving up looking for jobs.

Reagan learned this in the midst of negotiating historic arms-reduction treaties with the Soviets at the height of the Cold War.

It is clear, therefore, that the reserve reduction contemplated by the act will not be realized in practice.

If a company has no debts, a reduction in its capital made in an open manner in accordance with law, is legal.

On the 28th of March however it was found necessary to make a considerable reduction in the allowance.

That high-pressure engines owed their advantages mainly to a reduction of the relative importance of this latent heat.

This agreement caused a great reduction in the number of imports from Great Britain to these colonies.





reductio ad absurdumreduction division