In some non-technical contexts or in jargon, parameter may simply be a synonym for criterion.

In mathematics, statistics, and the mathematical sciences, parameters (L: auxiliary measure) are quantities that define certain relatively constant characteristics of systems or functions.

Most commonly represented θ in general form, other symbols carry standard, specific meanings. When evaluating the function over a domain or determining the response of the system over a period of time, the independent variables are modulated, while the parameters are held constant. The function or system may then be reevaluated or reprocessed with different parameters, to give a function or system with different behavior.