Akademik

umbilicus

n. (pl. umbilici or umbilicuses)
1 Anat. the navel.
2 Bot. & Zool. a navel-like formation.
3 Geom. a point in a surface through which all cross-sections have the same curvature.
Etymology: L, rel. to Gk omphalos and to NAVEL

Useful english dictionary. 2012.