Source : Webster's Revised Unabridged Dictionary (1913)

Nebulosity \Neb`u*los"i*ty\, n. [L. nebulositas: cf. F.
   n['e]bulosit['e]]
   1. The state or quality of being nebulous; cloudiness;
      hazeness; mistiness; nebulousness.

            The nebulosity . . . of the mother idiom. --I.
                                                  Disraeli.

   2. (Astron.)
      (a) The stuff of which a nebula is formed.
      (b) A nebula.