Definition of nebula in English:


Line breaks: neb¦ula
Pronunciation: /ˈnɛbjʊlə

noun (plural nebulae /-liː/ or nebulas)

1 Astronomy A cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
More example sentences
  • Evolutionists believe that the solar system condensed out of a cloud of gas and dust called a nebula, hence the nebular hypothesis.
  • We have missions that include active nebulas, swirling dust clouds, moving asteroids and asteroid fields.
  • A planetary nebula forms when Sun-like stars gently eject their outer gaseous layers to form bright nebulae with amazing twisted shapes.
1.1 dated A galaxy.
More example sentences
  • Then Edward Hubble discovered that the nebulae were other galaxies like ours only much further away than was thought possible.
  • In further studies, he showed that these nebulas are actually other galaxies, and he went on to classify them.
  • Hubble realized that these spiral nebulae were so far away they were actually galaxies - separate cities of stars - far beyond our own Milky Way.
2 Medicine A clouded spot on the cornea causing defective vision.
More example sentences
  • The bruise over his eye had settled in to a purple nearly matching the nebula itself, but the swelling had reduced dramatically.
  • It treats conjunctivitis, pterygium, nebula and pain in the eyes.


mid 17th century (as a medical term): from Latin, literally 'mist'.

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Word of the day flippant
Pronunciation: ˈflɪp(ə)nt
not showing a serious or respectful attitude