An Etymological Dictionary of the German Language/Nabel
Nabel, m., ‘navel,’ from the equiv. MidHG. nabel, OHG. nabolo, m.; corresponding to Du. navel, AS. nafela, E. navel, OIc. nafle, m., ‘navel’; Goth. *nabala is by chance not recorded. A common Aryan word in the primit. forms nobhelo-, onbhelo-; comp. Gr. ὀμφαλός, Lat. umbilîcus (for *unbilîcus, *nobilîcus), Sans. nâbhîla, OIr. imbliu, ‘navel.’ These words are primit. l- derivatives of OAryan nóbkâ, onbhâ, ‘nave, navel,’ appearing in Nabe. In other cases the OAryan terms for parts of the body are mostly underived forms (see Herz and Ohr).