reduction

[ri-duhk-shuhn]
noun
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-mm films to 16-mm for the school market.
7.
a village or settlement of Indians in South America established and governed by Spanish Jesuit missionaries.

Origin:
1475–85; earlier reduccion < Middle French reduction < Latin reductiōn- (stem of reductiō) a bringing back, equivalent to reduct(us) (past participle of redūcere; see reduce) + -iōn- -ion

reductional, adjective
antireduction, adjective
nonreduction, noun
nonreductional, adjective
overreduction, noun
proreduction, adjective
self-reduction, noun
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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
reduction (rɪˈdʌkʃən)
 
n
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
 a.  the process of converting a fraction into its decimal form
 b.  the process of dividing out the common factors in the numerator and denominator of a fraction; cancellation
 
re'ductive
 
adj

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Medical Dictionary

reduction re·duc·tion (rĭ-dŭk'shən)
n.

  1. The act, process, or result of reducing.

  2. The amount by which something is lessened or diminished.

  3. Restoration of an injured or dislocated part to its normal anatomical relation by surgery or manipulation. Also called repositioning.

  4. The first meiotic division, in which the chromosome number is reduced. Also called reduction division, reduction of chromosomes.

  5. A decrease in positive valence or an increase in negative valence by the gaining of electrons.

  6. A reaction in which hydrogen is combined with a compound.

  7. A reaction in which oxygen is removed from a compound.


re·duc'tion·al adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
reduction   (rĭ-dŭk'shən)  Pronunciation Key 
  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. Compare oxidation.


Our Living Language  : 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 (2H2) and one of oxygen (O2) combining to produce two molecules of water (2H2O), 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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American Heritage
Cultural Dictionary

reduction definition


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

Note: Reduction is the opposite of oxidation.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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FOLDOC
Computing Dictionary

reduction definition


(Or "contraction") The process of transforming an expression according to certain reduction rules. The most important forms are beta reduction (application of a lambda abstraction to one or more argument expressions) and delta reduction (application of a mathematical function to the required number of arguments).
An evaluation strategy (or reduction strategy), determines which part of an expression (which redex) to reduce first. There are many such strategies.
See graph reduction, string reduction, normal order reduction, applicative order reduction, parallel reduction, alpha conversion, beta conversion, delta conversion, eta conversion.
(1995-02-21)

The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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Example sentences
Deals that grant a reduction in teaching can end up lasting well beyond the
  reason they were handed out in the first place.
To prevent the silting, the government launched a livestock reduction program.
The handful of jobs lost from coal and natural gas reduction can be replaced
  double or triple by burning garbage.
The question is why this reduction in limb size happened.
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