Source : Webster's Revised Unabridged Dictionary (1913)

Nombril \Nom"bril\, n. [F. nombril, for OF. lombril, i. e.,
   ombril, with the article, a dim. fr. L. umbilicus the navel.
   See {Navel}.] (Her.)
   A point halfway between the fess point and the middle base
   point of an escutcheon; -- called also {navel point}. See
   {Escutcheon}.

Source : WordNet®

nombril
     n : the center point on a shield