NOUN (4)

1. a medicinal liquid preparation intended for use in an atomizer;

2. cloudiness of the urine;

3. an immense cloud of gas (mainly hydrogen) and dust in interstellar space;

4. (pathology) a faint cloudy spot on the cornea;

The Collaborative International Dictionary of English v.0.48:

Nebula \Neb"u*la\ (n[e^]b"[-u]*l[.a]), n.; pl. Nebulae
   (n[e^]b"[-u]*l[=e]). [L., mist, cloud; akin to Gr. nefe`lh,
   ne`fos, cloud, mist, G. nebel mist, OHG. nebul, D. nevel,
   Skr. nabhas cloud, mist. Cf. Nebule.]
   1. (Astron.) A faint, cloudlike, self-luminous mass of matter
      situated beyond the solar system among the stars. The term
      was originally applied to any diffuse luminous region.
      Now, technically, it is applied to interstellar clouds of
      dust and gases (diffuse nebula). However distant
      galaxies and very distant star clusters often appear like
      them in the telescope, such as the spiral nebula in
      Andromeda, known now to be a distant galaxy.
      [1913 Webster +PJC]

   2. (Med.)
      (a) A white spot or a slight opacity of the cornea.
      (b) A cloudy appearance in the urine. [Obs.]
          [1913 Webster]

WordNet (r) 3.0 (2006):

nebula
    n 1: a medicinal liquid preparation intended for use in an
         atomizer
    2: cloudiness of the urine
    3: an immense cloud of gas (mainly hydrogen) and dust in
       interstellar space
    4: (pathology) a faint cloudy spot on the cornea

The Free On-line Dictionary of Computing (19 January 2023):

Nebula

    An early business-oriented
   language from ICL for the Ferranti Orion computer.

   ["NEBULA - A Programming Language for Data Processing", T.G.
   Braunholtz et al, Computer J 4(3):197-201 (1961)].

   (1994-11-29)