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

Wallace said he had always been a keen photographer and had been on a learning curve with the tech involved in capturing outer space, including galaxies and nebula.

From BBC ● Aug. 13, 2026

The James Webb Space Telescope has captured new images of NGC 2392, a planetary nebula commonly known as the Lion Nebula, revealing the cosmic object in striking infrared detail.

From Science Daily ● Aug. 12, 2026

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

Every planetary nebula is a token of a star in extremis.

From "Cosmos" by Carl Sagan

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

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

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

From Space Scoop ● Oct. 31, 2025

The telescope’s size let it make images of very faint objects, and its high-quality mirror allowed it to distinguish individual stars in some of the nebulae.

From Salon ● Feb. 14, 2025

To test the distance of the spiral nebulae, a class of intrinsically much brighter variable stars was needed to furnish a new standard candle.

From "Cosmos" by Carl Sagan

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

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

According to our current understanding of solar systems, planets generally form out of the same nebulas that produce the stars that they orbit.

From Salon ● Dec. 29, 2021

I was rocketing through space, flying past exploding nebulas.

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