parameter noun. 1. (pə-rămʹĭ-tər) noun. 1. Mathematics. a. A constant in an equation that varies in other equations of the same general form, especially such a constant in the equation of a curve or surface that can be varied to represent a family of curves or surfaces. b. One of a set of independent variables that express the coordinates of a point, parameter; 2. (usually in plural) predetermined limit, had: the project has exceeded the parameters of the budget, projek itu telah melampaui had belanjawan yang diperuntukkan.