Umbilicus

umbilicus
1. (Science: anatomy) The depression, or mark, in the median line of the abdomen, which indicates the point where the umbilical cord separated from the foetus; the navel.
2. An ornamented or painted ball or boss fastened at each end of the stick on which manuscripts were rolled.
3. (Science: botany) The hilum.
4. (Science: zoology) A depression or opening in the center of the base of many spiral shells. Either one of the two apertures in the calamus of a feather.
5. (Science: geometry) One of foci of an ellipse, or other curve. 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.
Synonym: umbilic.
Origin: L. See Umbilic.