Source : Webster's Revised Unabridged Dictionary (1913)

Glabella \Gla*bel"la\, n.; pl. {Glabell?}. [NL., fr. L.
   glabellus hairless, fr. glaber bald.] (Anat.)
   The space between the eyebrows, also including the
   corresponding part of the frontal bone; the mesophryon. --
   {Gla*bel"lar}, a.

Glabellum \Gla*bel"lum\, n.; pl. {Glabella}. [NL. See
   {Glabella}.] (Zo["o]l.)
   The median, convex lobe of the head of a trilobite. See
   {Trilobite}.

Source : WordNet®

glabella
     n : a smooth prominence of the frontal bone between and above
         the eyebrows; the most forward projecting point of the
         forehead in the midline at the level of the supraorbital
         ridges [syn: {mesophyron}]
     [also: {glabellae} (pl)]