reductio

n. [ F. réduction, L. reductio. See Reduce. ] 1. The act of reducing, or state of being reduced; conversion to a given state or condition; diminution; conquest; as, the reduction of a body to powder; the reduction of things to order; the reduction of the expenses of government; the reduction of a rebellious province. [ 1913 Webster ]

2. (Arith. & Alg.) The act or process of reducing. See Reduce, v. t., 6. and To reduce an equation, To reduce an expression, under Reduce, v. t. [ 1913 Webster ]

3. (Astron.) (a) The correction of observations for known errors of instruments, etc. (b) The preparation of the facts and measurements of observations in order to deduce a general result. [ 1913 Webster ]

4. The process of making a copy of something, as a figure, design, or draught, on a smaller scale, preserving the proper proportions. Fairholt. [ 1913 Webster ]

5. (Logic) The bringing of a syllogism in one of the so-called imperfect modes into a mode in the first figure. [ 1913 Webster ]

6. (Chem. & Metal.) The act, process, or result of reducing{ 7 }; as, the reduction of iron from its ores; the reduction of an aldehyde into an alcohol. [ 1913 Webster ]

7. (Med.) The operation of restoring a dislocated or fractured part to its former place. [ 1913 Webster ]

Reduction ascending (Arith.), the operation of changing numbers of a lower into others of a higher denomination, as cents to dollars. --
Reduction descending (Arith.), the operation of changing numbers of a higher into others of a lower denomination, as dollars to cents. [ 1913 Webster ]

Syn. -- Diminution; decrease; abatement; curtailment; subjugation; conquest; subjection. [ 1913 Webster ]