parameter

para(beside)-meter

n.參數

wiki:

In mathematics, statistics, and the mathematical sciences, a parameter (G: auxiliary measure) is a quantity that serves to relate functions and variables using a common variable (often t) when such a relationship would be difficult to explicate with an equation

f(x) = ax² + bx + c;

here the variable x designates the function argument, but a, b, and c are parameters that determine which quadratic function one is considering.

字源：1656, from Mod.L. parameter  (1631), from Gk. para-  "beside, subsidiary" + metron  "measure" . A geometry term until 1920s when it yielded sense of "measurable factor which helps to define a particular system" (1927).