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

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

Called Nebula PMR 1, the object has a striking appearance that resembles a brain inside a transparent skull, which is why it has been nicknamed the "Exposed Cranium" nebula.

From Science Daily ● Mar. 17, 2026

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

From Science Daily ● Feb. 13, 2026

And some worlds will look out onto a vast gaseous nebula, the remains of an ordinary star that once was and is no longer.

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

These glowing regions are known as emission nebulae.

From Science Daily ● Dec. 25, 2025

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

From Space Scoop ● Oct. 31, 2025

Charles Messier also produced a catalog of over 100 prominent nebulae in 1781.

From Salon ● Feb. 14, 2025

Squinting, I could also make out a few tiny nebulae and galaxies in the distance.

From "Ready Player One: A Novel" by Ernest Cline

First observed in the early 1800s, the Helix Nebula has become one of the most recognizable planetary nebulas in the sky thanks to its bold, ring-like appearance.

From Science Daily ● Jan. 26, 2026

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