\U`ni*cur"sal\, a. [Uni- + L. currere, cursum, to
run.] (Geom.)
That can be passed over in a single course; -- said of a
curve when the co["o]rdinates of the point on the curve can
be expressed as rational algebraic functions of a single
parameter [theta].
Note: As [theta] varies minus infinity to plus infinity, to
      each value of [theta] there corresponds one, and only
      one, point of the curve, while to each point on the
      curve there corresponds one, and only one, value of
      [theta]. Straight lines, conic sections, curves of the
      third order with a nodal point, curves of the fourth
      order with three double points, etc., are unicursal.