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

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

The Dumbbell Nebula, also known as Messier 27, holds a special place in astronomy history as the first planetary nebula ever discovered.

From Science Daily ● Jun. 3, 2026

The collisions carve and sculpt the nebula, creating its intricate and textured appearance.

From Science Daily ● Jan. 26, 2026

The new data also highlights a clear transition from the hottest gas near the center to much cooler material farther out, as the nebula continues to expand away from its central star.

From Science Daily ● Jan. 26, 2026

Her dress was void black, mixed with the colors of a space nebula, as if galaxies were being born in her bodice.

From "The House of Hades" by Rick Riordan

As the hot core becomes exposed, it emits intense radiation that energizes the surrounding gas, producing the glowing shells seen in planetary nebulae such as the Helix, Stingray, and Butterfly nebulae.

From Science Daily ● Feb. 13, 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

As more data piled up, 19th century astronomers started to see that the nebulae were a mixed bag.

From Salon ● Feb. 14, 2025

Some scientists toyed with the idea that the spiral nebulae were not distant island universes but rather nearby condensing clouds of interstellar gas, perhaps on their way to make solar systems.

From "Cosmos" by Carl Sagan

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

From Science Daily ● Oct. 15, 2025

That they do through Jeff Russo's opening theme, which incorporates notes from the original series' melody with dreamy images of prismatic colored nebulas, jewel-like asteroid belts, and other mesmerizing sights along the Enterprise's cruising path.

From Salon ● Dec. 29, 2022

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

I was rocketing through space, flying past exploding nebulas.

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