nebula

American  

[neb-yuh-luh] / ˈnɛb jə lə /

noun

nebulae, plural nebulas plural

1. Astronomy.

   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.

2. Pathology.

   1. a faint opacity in the cornea.

   2. cloudiness in the urine.

3. any liquid medication prepared for use as a spray.

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nebula British  

/ ˈnɛbjʊlə /

noun

1. 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

2. pathol

   1. opacity of the cornea

   2. cloudiness of the urine

3. any substance for use in an atomizer spray

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nebula Scientific  

/ nĕb′yə-lə /

nebulae plural

1. 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.

2. ◆ 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.

3. See more at star

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nebula Cultural  

1. 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.

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Other Word Forms

Derived Forms

• nebular
  adjective
• nonnebular
  adjective
• prenebular
  adjective

Inflected Forms

Nouns

• nebulae
  plural
• nebulas
  plural

Etymology

Origin of nebula

First recorded in 1655–65; from Latin: “cloud, mist, vapor”; akin to German Nebel “fog, haze,” Greek nephélē “cloud,” Sanskrit nábha- “cloud, vapor”

Explanation

A nebula is a massive cloud of gas and dust in outer space. A nebula is sometimes the birthplace of stars, such as the Orion Nebula where new stars — a youthful million years old — are still forming. Another example of a nebula is the Crab Nebula — the glowing result of a supernova, noted by Chinese astronomers in 1054 CE. It spans about 10 light-years in length. In biology, a nebula may be a cloudy formation in the eye, or a cloudiness of urine. It also refers to a medicinal preparation put in a nebulizer. When you are talking about more than one nebula (which is probably not that often for the average person), say nebulae.

Example Sentences

See Examples For:

nebula nebulae nebulas

Those energetic forces heat the surrounding hydrogen gas and gradually sculpt the nebula into its striking appearance.

From Science Daily ● Jul. 5, 2026

"Then we directly compared our simulations with other laboratory experiments that produce COMs under realistic astrophysical conditions. The results showed that COM formation is possible in both the protosolar nebula environment and Jupiter's circumplanetary disk."

From Science Daily ● Mar. 1, 2026

This means the Galilean moons may have inherited organic material from two sources: the wider solar nebula and local chemical activity within Jupiter's own disk billions of years ago.

From Science Daily ● Mar. 1, 2026

It is the first, youngest, and closest pre-planetary nebula ever identified.

From Science Daily ● Feb. 13, 2026

To their surprise, they found an intense and previously unreported source that seemed to correspond to no prominent star, nebula or galaxy.

From "Cosmos" by Carl Sagan

The project uses Hubble's Wide Field Camera 3, an instrument capable of resolving individual star clusters and nebulae in galaxies located tens of millions of light-years away.

From Science Daily ● Jun. 1, 2026

"V1298Tau is a critical link between the star/planet forming nebulae we see all over the sky, and the mature planetary systems that we have now discovered by the thousands."

From Science Daily ● Jan. 31, 2026

That’s why such nebulae are often called stellar nurseries.

From Space Scoop ● Oct. 31, 2025

Shapley argued that the spiral nebulae were small and in the Milky Way, while Curtis took a more radical position that they were independent galaxies, extremely large and distant.

From Salon ● Feb. 14, 2025

“Well, in the language of the nebulae it’s actually—” She made a series of crackling and blowing noises that reminded Frank of a thunderstorm giving way to a nice cold front.

From "The Son of Neptune" by Rick Riordan

Another concerns the gaseous nebulas in which the planets and their stars formed.

From Science Daily ● Oct. 15, 2025

Gorgeous photographs of swirling galaxies, fiery nebulas and newborn stars stunned the world.

From Scientific American ● Dec. 1, 2022

Nowadays, of course, they are available instantaneously, on demand and, essentially, for free via the internet — along with photographs of nebulas and stars from even deeper in space.

From Washington Post ● Nov. 23, 2022

In July, the Webb, the largest-ever space telescope, enthralled both scientists and the public with spectacular glimpses of never-before-seen nebulas, exoplanets, ancient galaxies, and fluffy translucent clouds of space dust swirling around shimmering stars.

From New York Times ● Oct. 13, 2022

I was rocketing through space, flying past exploding nebulas.

From "Klawde: Evil Alien Warlord Cat" by Johnny Marciano and Emily Chenoweth