What is "umbilic"

Umbilicus \Um`bi*li"cus\, n. [L. See Umbilic.]

1. (Anat.) The depression, or mark, in the median line of the abdomen, which indicates the point where the umbilical cord separated from the fetus; the navel.

2. (Gr. & Rom. Antiq.) An ornamented or painted ball or boss fastened at each end of the stick on which manuscripts were rolled.
   --Dr. W. Smith.

3. (Bot.) The hilum.

4. (Zo["o]l.)

   1. A depression or opening in the center of the base of many spiral shells.

   2. Either one of the two apertures in the calamus of a feather.

5. (Geom.)

   1. One of foci of an ellipse, or other curve. [Obs.]

   2. A point of a surface at which the curvatures of the normal sections are all equal to each other. A sphere may be osculatory to the surface in every direction at an umbilicus. Called also umbilic.

a. Of, pertaining to, or having a navel or umbilicus n. 1 The navel; the center. 2 (context geometry English) An umbilicus.