Definition of: umbilicus

(um·bil′ə·kəs, um′bə·lī′kəs) noun plural ·ci (-sī)
1. Anat. The depression at the middle of the abdomen where the umbilical cord of the fetus was attached; the navel.
2. Zool. An indention or depression at the axial base of a spiral shell, as in many gastropods.
3. Ornithol. Either of the apertures (inferior and superior) of the calamus of a feather.
4. Bot. A navel-shaped depression; a hilium. [<L]