Definitions
1.nounA value kept constant during an experiment, equation, calculation or similar, but varied over other versions of the experiment, equation, calculation, etc.
2.nounA variable that describes some system (material, object, event etc.) or some aspect thereof
3.nounAn input variable of a procedure definition, that gets an actual value (argument) at execution time (formal parameter)."Roughly, a tuple of arguments could be thought of as a vector, whereas a tuple of parameters could be thought of as a covector (i.e., linear functional). When a function is called, a parameter tuple becomes "bound" to an argument tuple, allowing the function instance itself to be computed to yield a return value. This would be roughly analogous to applying a covector to a vector (by taking their dot product (or, rather, matrix-product of row vector and column vector)) to obtain a scalar."
4.nounAn actual value given to such a formal parameter (argument or actual parameter).
5.nounA characteristic or feature that distinguishes something from others.
6.nounIn the ellipse and hyperbola, a third proportional to any diameter and its conjugate, or in the parabola, to any abscissa and the corresponding ordinate."The parameter of the principal axis of a conic section is called the latus rectum."
7.nounThe ratio of the three crystallographic axes which determines the position of any plane.
8.nounThe fundamental axial ratio for a given species.