in the schools, signifies a manner of bringing a term or proposition which was before opposite to some other, to be equivalent to it.

in Arithmetic, that rule by which numbers of different denominations are brought into one denomination.

Reduction of Equations, in Algebra, is the clearing them from all superfluous quantities, bringing them to their lowest terms, and separating the known from the unknown, till at length only the unknown quantity is found upon one side, and the known ones on the other. The reduction of an equation is the last part of the resolution of the problem.