noun
The fully shaded inner region of a shadow cast by an opaque object.
(astronomy) The central region of a sunspot.
(chiefly literary) A shadow.
(archaic) An uninvited guest brought along by one who was invited.
One of the family Umbridae of mudminnows.
One of genus Umbrina of drums (family Sciaenidae).
(mathematics) An element of the umbral calculus.