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 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

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

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

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

"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

These glowing structures form two long, narrow nebulae driven by intense activity around a supermassive black hole at the galaxy's core.

From Science Daily ● Jan. 10, 2026

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

From Space Scoop ● Oct. 31, 2025

He believed that the nebulae were objects within the Milky Way.

From Salon ● Feb. 14, 2025

When we look around us in our little corner of the Milky Way, we see many stars surrounded by spherical shells of glowing gas, the planetary nebulae.

From "Cosmos" by Carl Sagan

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

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