Pa-răm'e-ter, n.

n. [Fr. paramètre, from Gr. παρά, beside, and μέτρον, measure.] (Geom.) In general, any straight line or numerical co-efficient by the value of which one individual curve of a species may be distinguished from the rest; hence (Conic Sections), 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.