Pa*ram"e*ter (?), n. [Pref. para-
+ -meter: cf. F. paramètre.] 1.
(a) (Math.) A term applied to some
characteristic magnitude whose value, invariable as long as one and
the same function, curve, surface, etc., is considered, serves to
distinguish that function, curve, surface, etc., from others of the
same kind or family. Brande & C. (b)
Specifically (Conic Sections), 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.
&fist; The parameter of the principal axis of a conic
section is called the latus rectum.
2. (Crystallog.) The ratio of the three
crystallographic axes which determines the position of any plane;
also, the fundamental axial ratio for a given species.
