from
The Collaborative International Dictionary of English v.0.48
Unicursal \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 coordinates of the point on the curve can be
expressed as rational algebraic functions of a single
parameter [theta].
[1913 Webster]
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.
[1913 Webster]