Umbilic n. : The navel; the center.

Umbilic n. : An umbilicus. See Umbilicus, 5 (b).

Umbilic a. : See Umbilical, 1.

Example:
Umbilic cord on newborn

Taxonomy
umbilic, Umbilical point, free encyclopedia, configurations, principal direction, star, lemon, normal vector, elliptical region, Gaussian curvature, Riemannian manifolds, the normal, tangent vector, lines of curvature, search, three dimensions, locally, isolated points.

Defination from the web:
... curvature where every point is umbilic. The monkey saddle is an example of a surface which has an umbilic at a point where the Gaussian ... The classification determines the number of ridge lines passing through the umbilic (either 1 or 3) and the index of the principal direction ...