nebulosity

from The Collaborative International Dictionary of English v.0.48

Nebulosity \Neb`u*los"i*ty\, n. [L. nebulositas: cf. F.
   n['e]bulosit['e]]
   1. The state or quality of being nebulous; cloudiness;
      haziness; mistiness; nebulousness.
      [1913 Webster]

            The nebulosity . . . of the mother idiom. --I.
                                                  Disraeli.
      [1913 Webster]

   2. (Astron.)
      (a) The stuff of which a nebula is formed.
      (b) A nebula.
          [1913 Webster]