Source : Webster's Revised Unabridged Dictionary (1913)

Invisibility \In*vis`i*bil"i*ty\, n.; pl. {Invisibilities}. [L.
   invisibilitas: cf. F. invisibilit['e].]
   The state or quality of being invisible; also, that which is
   invisible. ``Atoms and invisibilities.'' --Landor.

Source : WordNet®

invisibility
     n : the quality of not being perceivable by the eye [syn: {invisibleness}]
         [ant: {visibility}]