nebula
//ˈnɛbjʊlə//
Noun
nebulaSingular
nebulaePlural
1
A cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter.
The Orion Nebula is one of the brightest nebulae visible to the naked eye.
2
A clouded spot on the cornea causing defective vision.
The doctor discovered a small nebula on the patient's cornea during the eye examination.