umbilic

from The Century Dictionary.

• noun In geometry, a point of a surface where the radii of curvature are all equal, and a sphere osculates the surface.
• Same as umbilical.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete The navel; the center.
• noun (Geom.) An umbilicus. See Umbilicus, 5 (b).
• adjective (Anat.) See umbilical, 1.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Of, pertaining to, or having a navel or umbilicus