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-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.

reduction

/ rɪˈdʌkʃən /

noun

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

reduction

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

reduction

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

Usage

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.

Reduction is the opposite of oxidation.

Other Word Forms

• reductional adjective
• antireduction adjective
• nonreduction noun
• nonreductional adjective
• overreduction noun
• proreduction adjective
• self-reduction noun
• reductive adjective

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

Example Sentences

Proposals include stopping welfare claims for people with "low level mental health problems" and reducing the number of civil servants by around 132,000, a reduction of around a quarter.

From BBC

Soon he will decide what "Democrat agencies" he would cut and whether those reductions would be temporary or permanent.

From BBC

Under the scheme, the discount applies to new eligible car models costing up to £37,000, with the most environmentally friendly ones seeing the biggest reductions.

From BBC

But researchers like Prof Pepin-Neff say the nets aren't very effective, and give the illusion of safety rather than delivering a real reduction in risk.

From BBC

Google said it plans to lay off dozens of workers at its Sunnyvale offices, following job reductions at other large tech firms.

From Los Angeles Times

Related Words

• contraction 
• cut 
• cutback 
• devaluation 
• discount 
• rebate