- 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.
- An ornamented or painted ball or boss fastened at each
end of the stick on which manuscripts were rolled.
- The hilum.
- 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
- 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. Called also umbilic.