nebula

noun

neb·​u·​la ˈne-byə-lə 

plural nebulae ˈne-byə-ˌlē  -ˌlī  also nebulas

1

: any of numerous clouds of gas or dust in interstellar space

2

: galaxy sense 1b

especially : a galaxy other than the Milky Way galaxy

—not used technically

nebular

ˈne-byə-lər 

adjective

Did you know?

The history of nebula belongs not to the mists of time but to the mists of Latin: in that language nebula means "mist" or "cloud." In its earliest English uses in the 1600s, nebula was chiefly a medical term that could refer either to a cloudy formation in urine or to a cloudy speck or film on the eye. Nebula was first applied to great interstellar clouds of gas and dust in the early 1700s. The adjective nebulous comes from the same Latin root as nebula, and it is considerably older, being first used as a synonym of cloudy or foggy as early as the 1300s. Like nebula, this adjective was not used in an astronomical sense until centuries later.

Examples of nebula in a Sentence

Recent Examples on the Web

As per Starwalk, the comet will trace a line over the course of the month, starting in the constellation Eridanus on May 4, and moving up through Orion toward the Red Rectangle nebula. —Tom Hawking, Popular Science, 30 Apr. 2026

How to observe nebulas There are many types of nebulas, and most disappoint the beginner. —Jamie Carter, Space.com, 28 Apr. 2026

After first capturing an image of the nebula in 1997, Hubble once again trained its sights on the region not just to return an even more striking photo, but to provide insights into how young stars interact with their surroundings, NASA said. —Eric Lagatta, USA Today, 27 Apr. 2026

Finding this molecule in a nebula would change how scientists think about the evolution of life’s ingredients. —Olivia Harper Wilkins, The Conversation, 27 Apr. 2026

Word History

Etymology

New Latin, from Latin, mist, cloud; akin to Old High German nebul fog, Greek nephelē, nephos cloud

First Known Use

1718, in the meaning defined at sense 1

Phrases Containing nebula

• planetary nebula

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Kids Definition

nebula

noun

neb·​u·​la ˈneb-yə-lə 

plural nebulas or nebulae -ˌlē 

-ˌlī

1

: any of many huge clouds of gas or dust in deep space

2

: galaxy sense 2

nebular

-lər 

adjective

Medical Definition

nebula

noun

neb·​u·​la ˈneb-yə-lə 

plural nebulas or nebulae -ˌlē  -ˌlī 

: a slight cloudy opacity of the cornea