Umbilicus /(?)/

Um·bi·li·cus

Umbilicus

n.
  1. 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; the belly button, in humans. (Anat.)
  2. An ornamented or painted ball or boss fastened at each end of the stick on which manuscripts were rolled. (Gr. & Rom. Antiq.)
  3. The hilum. (Bot.)
  4. A depression or opening in the center of the base of many spiral shells. (Zool.)
  5. One of the foci of an ellipse, or other curve. (Geom.) [Obs.]