nebula

The definition of a nebula is a cloud of gas and dust in outer space.

(noun)

A mass of dust in the sky that reflects light and appears as darkness in the sky may be an example of a nebula.

See nebula in Webster's New World College Dictionary

a cloud of interstellar gas or dust: formerly, applied to any hazy, distant celestial object, as a star cluster or an external galaxy
Med.
1. a small, cloudy opacity on the cornea
2. a liquid preparation used as a spray

Origin: ModL < L, vapor, fog, mist < IE base *nebh-, moist, vapor, cloud > Gr nephos, nephelē, cloud, OE nifol, mist, darkness

Related Forms:

See nebula in American Heritage Dictionary 4

noun pl. neb·u·lae (-lēˌ) or neb·u·las

Astronomy
a. A diffuse mass of interstellar dust or gas or both, visible as luminous patches or areas of darkness depending on the way the mass absorbs or reflects incident radiation.
b. See galaxy.
Pathology
a. A cloudy spot on the cornea.
b. Cloudiness in the urine.
A liquid medication applied by spraying.

Origin:

Origin: Middle English nebule, cloud, mist

Origin: , from Latin nebula; see nebh- in Indo-European roots

Related Forms: