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[neb-yuh-luh] /ˈnɛb yə lə/
noun, plural nebulae
[neb-yuh-lee, -lahy] /ˈnɛb yəˌli, -ˌlaɪ/ (Show IPA),
  1. Also called diffuse nebula. a cloud of interstellar gas and dust.
  2. (formerly) any celestial object that appears nebulous, hazy, or fuzzy, and extended in a telescope view.
  1. a faint opacity in the cornea.
  2. cloudiness in the urine.
any liquid medication prepared for use as a spray.
Origin of nebula
1655-65; < Latin: a mist, vapor, cloud; akin to Greek nephélē cloud, German Nebel fog, haze
Related forms
nebular, adjective
nonnebular, adjective
prenebular, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for nebulae


noun (pl) -lae (-ˌliː), -las
(astronomy) a diffuse cloud of particles and gases (mainly hydrogen) that is visible either as a hazy patch of light (either an emission or a reflection nebula) or an irregular dark region against a brighter background (dark nebula) Compare planetary nebula
  1. opacity of the cornea
  2. cloudiness of the urine
any substance for use in an atomizer spray
Derived Forms
nebular, adjective
Word Origin
C17: from Latin: mist, cloud; related to Greek nephétē cloud, Old High German nebul cloud, Old Norse njól night
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for nebulae



early 15c., nebule "a cloud, mist," from Latin nebula "mist, vapor, fog, smoke, exhalation," figuratively "darkness, obscurity," from PIE *nebh- "cloud" (cf. Sanskrit nabhas- "vapor, cloud, mists, fog, sky;" Greek nephele, nephos "cloud;" German nebel "fog;" Old English nifol "dark, gloomy;" Welsh niwl "cloud, fog;" Slavic nebo).

Re-borrowed from Latin 1660s in sense of "cataracts in the eye;" astronomical meaning "cloud-like patch in the night sky" first recorded c.1730. As early as Hershel (1802) astronomers realized that some nebulae were star clusters, but certain distinction of relatively nearby cosmic gas clouds from distant galaxies was not made until 1920s, using the new 100-inch Mt. Wilson telescope.

Online Etymology Dictionary, © 2010 Douglas Harper
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nebulae in Medicine

nebula neb·u·la (něb'yə-lə)
n. pl. neb·u·las or neb·u·lae (-lē')

  1. A faint, foglike opacity of the cornea.

  2. A class of oily preparations for use in a nebulizer.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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nebulae in Science
Plural nebulae (něb'yə-lē') or nebulas
A visible, thinly spread cloud of interstellar gas and dust. Some nebulae are the remnants of a supernova explosion, others are gravity-induced condensations of the gases in the interstellar medium which in certain cases may become a site for the formation of new stars. The term was formerly used of any hazy, seemingly cloudlike object, including what are now recognized as other galaxies beyond the Milky Way; it is restricted now to actual clouds of gas and dust within our own galaxy. ◇ Nebulae are generally classified as bright or dark. Among the bright nebulae are cold clouds that reflect light from nearby stars (reflection nebulae) and hot, ionized clouds that glow with their own light (emission nebulae). Dark nebulae—cold clouds that absorb the passing light from background stars—are called absorption nebulae. See more at star.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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nebulae in Culture
nebula [(neb-yuh-luh)]

plur. nebulae

In astronomy, a hazy patch of light visible in the sky. Some nebulae are clouds of gas within the Milky Way; others are distant galaxies. (See photo, next page.)

The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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