Nebula

 WORD OF THE DAY

nebula / noun / NEB-yuh-luh

Definition
1 : any of numerous clouds of gas or dust in interstellar space
2: galaxy; especially a galaxy other than the Milky Way

Examples
"Many nebulae are today known and loved by their numbers in [the New General Catalogue of Nebulae and Clusters of Stars]: NGC 6822 is a faint nearby irregular galaxy, NGC 7027 is a planetary nebula, NGC 6960 is a supernova remnant…."
— Frederick R. Chromey, To Measure the Sky, 2010

"[Edwin] Hubble determined M31 was millions of light years away, and was actually another galaxy, rather than a nebula in our own galaxy."
— Marcy Curran, The Wyoming Tribune Eagle (Cheyenne, Wyoming), 30 Oct. 2020

Did You Know?
The history of today's word is not lost in the mists of time, although its history does get misty at points. Nebula comes to us from Latin, where it 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 that caused vision problems.
It 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, however, this adjective was not used in an astronomical sense until the mid-1600s.