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

The next image highlights NGC 3603, a nebula in the Milky Way that contains an enormous cluster of young stars.

From Science Daily ● Jul. 4, 2026

Inside this nebula, particle interactions can generate gamma rays in several ways.

From Science Daily ● May 27, 2026

Together, these particles create a huge cloud of high-energy material called a magnetar wind nebula.

From Science Daily ● May 27, 2026

Chandeliers with Pleiades Corp’s signature color, royal purple, illuminating the faces of actors in fancy clothes, holding martini glasses and smiling as they stared out at a fake nebula.

From "The Last Cuentista" by Donna Barba Higuera

Its relatively close distance and clear visibility make it a key object for studying neutron stars, supernova remnants, and nebulae.

From Science Daily ● Mar. 28, 2026

These sources include pulsars, planetary nebulae, compact HII regions -- which are dense, ionized gas clouds in space -- as well as distant galaxies that lie far beyond the Milky Way.

From Science Daily ● Jan. 24, 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

I just stared at the chalk nebulae on the blackboard.

From "Black Swan Green" by David Mitchell

As one of the closest planetary nebulas to Earth, it offers astronomers a rare opportunity to closely examine the final stages of a star's life.

From Science Daily ● Jan. 26, 2026

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

From Scientific American ● Dec. 1, 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

Known as the Bubble Nebula, or NGC 7635, it is an emission nebula located 8 000 light-years away; emission nebulas are interstellar clouds which are comprised of ionized gases.

From Salon ● Apr. 23, 2022

As a result, the histories of dinosaurs, nebulas, and glaciers are generally acknowledged to belong to fields of science rather than to the humanities.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond