from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The act or process of reducing.
  • n. The result of reducing: a reduction in absenteeism.
  • n. The amount by which something is lessened or diminished: a reduction of 12 percent in violent crime.
  • n. Biology The first meiotic division, in which the chromosome number is reduced. Also called reduction division.
  • n. Chemistry A decrease in positive valence or an increase in negative valence by the gaining of electrons.
  • n. Chemistry A reaction in which hydrogen is combined with a compound.
  • n. Chemistry A reaction in which oxygen is removed from a compound.
  • n. Mathematics The canceling of common factors in the numerator and denominator of a fraction.
  • n. Mathematics The converting of a fraction to its decimal equivalent.
  • n. Mathematics The converting of an expression or equation to its simplest form.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The act, process, or result of reducing.
  • n. The amount or rate by which something is reduced, e.g. in price.
  • n. A reaction in which electrons are gained and valence is reduced; often by the removal of oxygen or the addition of hydrogen.
  • n. The process of rapidly boiling a sauce to concentrate it.
  • n. The rewriting of an expression into a simpler form.
  • n. a transformation of one problem into another problem, such as mapping reduction or polynomial reduction.
  • n. An arrangement for a far smaller number of parties, e.g. a keyboard solo based on a full opera.
  • n. A philosophical procedure intended to reveal the objects of consciousness as pure phenomena. (See phenomenological reduction.)
  • n. A medical procedure to restore a fracture or dislocation to the correct alignment.

from the GNU version of the Collaborative International Dictionary of English

  • n. The act of reducing, or state of being reduced; conversion to a given state or condition; diminution; conquest
  • n. The act or process of reducing. See Reduce, v. t., 6. and To reduce an equation, To reduce an expression, under Reduce, v. t.
  • n.
  • n. The correction of observations for known errors of instruments, etc.
  • n. The preparation of the facts and measurements of observations in order to deduce a general result.
  • n. The process of making a copy of something, as a figure, design, or draught, on a smaller scale, preserving the proper proportions.
  • n. The bringing of a syllogism in one of the so-called imperfect modes into a mode in the first figure.
  • n. The act, process, or result of reducing{7}.
  • n. The operation of restoring a dislocated or fractured part to its former place.

from The Century Dictionary and Cyclopedia

  • n. The act of reducing, or the state of being reduced.
  • n. Conversion into another state or form: as, the reduction of a body to powder; the reduction of things to order.
  • n. (c.) Diminution: as, the reduction of the expenses of government; the reduction of the national debt; a reduction of 25 per cent. made to wholesale buyers.
  • n. Conquest; subjugation: as, the reduction of a province under the power of a foreign nation; the reduction of a fortress.
  • n. A settlement or parish of South American Indians converted and trained by the Jesuits.
  • n. The bringing of a problem to depend on a problem already solved.
  • n. The transformation of an algebraic expression into another of a simpler kind.
  • n. The lowering of the values of the numerator and denominator of a fraction, or of the antecedent and consequent of a ratio, by dividing both by the same quantity.
  • n. The conversion of a quantity expressed in terms of one denomination so as to express it in terms of another denomination. Ascending reduction is conversion to terms of larger units; descending reduction, conversion to terms of smaller units.
  • n. The proof of the conclusion of an indirect syllogism from its premises by means of a direct syllogism and immediate inferences. This is said to be a reduction to the mode of direct syllogism employed.
  • n. A direct syllogism proving, by means of conversions and other immediate inferences, that the conclusion of an indirect syllogism follows from its premises.
  • n. The act or process of making a copy of a figure, map, design, draft, etc., on a smaller scale, preserving the original proportions; also, the result of this process.
  • n. In surg, the operation of restoring a dislocated or fractured bone to its former place.
  • n. Separation of a metal from substances combined with it: used especially with reference to lead, zinc, and copper, and also applied to the treatment of iron ore, as when steel is made from it by a direct process.
  • n. In astronomy, the correction of observed quantities for instrumental errors, as well as for refraction, parallax, aberration, precession, and nutation, so as to bring out their cosmical significance. A similar process is applied to observations in other physical sciences.
  • n. In Scots law, an action for setting aside a deed, writing, etc.
  • n. Synonyms Lessening decrease, abatement, curtailment, abridgment, contraction. retrenchment.
  • n. In linguistics, the shortening of a word by apocope.
  • n. In cytology, the halving of the number of somatic chromosomes during spermatogenesis and oögenesis.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent
  • n. the act of decreasing or reducing something
  • n. the act of reducing complexity


from The American Heritage® Dictionary of the English Language, 4th Edition

Middle English reduccion, restoration, from Old French reduction, from Latin reductiō, reductiōn-, from reductus, past participle of redūcere, to bring back; see reduce.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English reduccion, from Old French reducion, from Latin reductio.


  • The term reduction is often used to refer to the relation between a theory and its historical successor.

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  • You see, this reduction is all about reducing weight for the launch of the ISS-Trimmed Orion on Ares-I.

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  • But the word "reduction" was dropped in the editing process.

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  • Analysts believe that the reduction is already stimulating investment and helping to boost economic growth.

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  • "My assessment is that we will see a short term reduction in Chinese deals with Iran, but ultimately China will re-enter the market with gusto and take as much Iranian oil as it can, while it can, at rock bottom prices." - Telegraph online, Daily Telegraph and Sunday Telegraph

  • The keyway was a situation where those -- that company was bankrupt, but we did introduce some credentialization, if you will, in terms of strengthening the management, as well as the training of the organization, then left to a short term reduction in the number of sales people.

  • With respect to what they call the reduction of the debt from its nominal sum, it is not a reduction of it, but an appreciation at its true value.

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  • Whether or not it's an RPU opportunity for you, or whether you are viewing it basically the way you're viewing the current satellite offer and it's a term reduction opportunity. Home Page

  • The term reduction of suffering over the unpleasant or unpleasantness commonly enhancement of happiness when speaking means painful or painfulness in a broad of utility: "I believe that there is, from the sense.

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  • Many studies have shown that class size reduction is cost-effective because it results in higher wages later in life (see the above study, for example), and lower costs for health care and/or welfare dependency.

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