Definition of: lemniscate

(lem′nis·kāt, -kit) noun Math.
The plane curve in the shape of a figure eight traced by the foot of a perpendicular drawn from the origin to a tangent to a rectangular hyperbola: the locus of the vertex of a triangle when the product of the two adjacent sides is maintained equal to 1/4 of the fixed, opposite side. Also called Bernoulli's lemniscate. [<NL lemniscata, orig. fem. of L lemniscatus adorned with ribbons <lemniscus. See LEMNISCUS.]
LEMNISCATE
A symmetrical tracing in polar coordinates.