n. In mathematics, a real positive number that serves as measure or parameter of a function or effect. Represented by M. or μ.n. In physics, the measure of an effect under conditions whose measure is unity. Thus, a physical modulus is not a number, but a physical quantity.n. [capitalized] In conchology, a genus of gastropods, referred to the Littorinidæ or periwinkles, or made type of the family Modulidæ. The shell is depressed and trochiform, with a deeply cut columellar tooth and many-whorled operculum.n. then the modulus of transformation is