To make manifold; increase in number or quantity; make more by natural generation or reproduction, or by accumulation, addition, or repetition: as, to multiply men or horses; to multiply evils.In arithmetic, to perform the operation of multiplication upon. See multiplication, 2.To increase (the precious metals) by alchemical means. See multiplication, 3.To grow or increase in number or extent; extend; spread.In arithmetic, to perform the process of multiplication. See multiplication, 2.To increase gold or silver by alchemical means.In a manifold way.