reduction

Etymology

From Middle English reduccion, a borrowing from Old French reducion, from Latin reductiō, reductiōnem.

noun

1. The act, process, or result of reducing.
   With the cutting out of the previous recovery times for electrification work, curtailment of station times and acceleration, considerable reductions have been made in the overall schedules. 1961 January, “The North-East London electrification of the Great Eastern Line”, in Trains Illustrated, page 18
2. The amount or rate by which something is reduced, e.g. in price.
   A 5% reduction in robberies
3. (chemistry) A reaction in which electrons are gained and valence is reduced; often by the removal of oxygen or the addition of hydrogen.
4. (cooking) The process of rapidly boiling a sauce to concentrate it.
5. (mathematics) The rewriting of an expression into a simpler form.
6. (computability theory) a transformation of one problem into another problem, such as mapping reduction or polynomial reduction.
7. (music) An arrangement for a far smaller number of parties, e.g. a keyboard solo based on a full opera.
8. (philosophy, phenomenology) A philosophical procedure intended to reveal the objects of consciousness as pure phenomena. (See phenomenological reduction.)
9. (medicine) A medical procedure to restore a fracture or dislocation to the correct alignment, usually with a closed approach but sometimes with an open approach (surgery).
   closed reduction
   open reduction and internal fixation
10. (paying) A reduced price of something by a fraction or decimal.
11. (metalworking) The ratio of a material's change in thickness compared to its thickness prior to forging and/or rolling.
    The final stage of thickness reduction (typically 90% from about 2mm to <0.2mm) is carried out by cold rolling. 2016, Gordon L. Robertson, Food Packaging Principles and Practice, 3rd edition, page 191