from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Astronomy A diffuse mass of interstellar dust or gas or both, visible as luminous patches or areas of darkness depending on the way the mass absorbs or reflects incident radiation.
  • n. Astronomy See galaxy.
  • n. Pathology A cloudy spot on the cornea.
  • n. Pathology Cloudiness in the urine.
  • n. A liquid medication applied by spraying.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A cloud in outer space consisting of gas or dust (e.g. a cloud formed after a star explodes).
  • n. A white spot or slight opacity of the cornea.
  • n. A cloudy appearance in the urine

from the GNU version of the Collaborative International Dictionary of English

  • n. 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.
  • n.
  • n. A white spot or a slight opacity of the cornea.
  • n. A cloudy appearance in the urine.

from The Century Dictionary and Cyclopedia

  • n. A luminous patch in the heavens, far beyond the limits of the solar system.
  • n. In pathology, a cloud-like spot on the cornea.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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


Middle English nebule, cloud, mist, from Latin nebula.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin nebula ("little cloud", "mist"). Akin to Greek νεφέλη, "cloud", German Nebel, "mist", "nebula", Old Norse nifl. (Wiktionary)



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