A Parameter

1. A value kept constant during an experiment, equation, calculation or similar, but varied over other versions of the experiment, equation, calculation, etc. Parameter - Wikipedia
2. (sciences) a variable that describes some system (material, object, event etc.) or some aspect thereof
3. (programming) An input variable of a procedure definition, that gets an actual value (argument) at execution time (formal parameter).
4. (programming) An actual value given to such a formal parameter (argument or actual parameter).
5. A characteristic or feature that distinguishes something from others.
6. (geometry) In the ellipse and hyperbola, a third proportional to any diameter and its conjugate, or in the parabola, to any abscissa and the corresponding ordinate.
7. (crystallography) The ratio of the three crystallographic axes which determines the position of any plane.
8. (crystallography) The fundamental axial ratio for a given species.

Usage notes

• (the value used to instantiate the name): Some authors regard use of parameter to mean argument as imprecise, preferring that parameter refers only to the name that will be instantiated, and argument to refer to the value that will be supplied to it at runtime.

Synonyms

• (value passed to a function): argument
• (characteristic distinguishing something from others): distinguishing feature
• characteristic