Parameter -

• Representation of a physical quantity; often used in an equation relating several parameters. Example: The equation F=ma relates the parameters of net force (F) applied on a body to that body's mass (m) and acceleration (a).

• Quantity (quantifiable physical property) used within a basis which characterizes a particular object or system or its state. Such things as spatial dimensions, temperature, conductance, mass etc. are parameters.

• Vector - A parameter can be represented in vector form if it has a magnitude and direction. The magnitude and direction of the vector may be represented by equations which are a function of position or other variables.

• From Greek:  para=alongside, metron=to measure.