- The definition of a nebula is a cloud of gas and dust in outer space.
A mass of dust in the sky that reflects light and appears as darkness in the sky may be an example of a nebula.
The Orion Nebula.
nounpl. nebulae or nebulas
- a cloud of interstellar gas or dust: formerly, applied to any hazy, distant celestial object, as a star cluster or an external galaxy
- a small, cloudy opacity on the cornea
- a liquid preparation used as a spray
Origin of nebulaModern Latin ; from Classical Latin vapor, fog, mist ; from Indo-European base an unverified form nebh-, moist, vapor, cloud from source Classical Greek nephos, nephelē, cloud, Old English nifol, mist, darkness
nounpl. neb·u·lae or neb·u·las
- Astronomy a. A diffuse cloud 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 light or emits its own light.b. A galaxy. No longer in technical use.
- Medicine a. A cloudy spot on the cornea.b. A liquid preparation for use in a nebulizer.
Origin of nebulaMiddle English nebule, cloud, mist, from Latin nebula; see nebh- in Indo-European roots.
the Crab Nebula, photographed by the Hubble Space Telescope in 2005
(plural nebulae or nebulas)
From Latin nebula (“little cloud", "mist”). Akin to Greek νεφέλη, "cloud", German Nebel, "mist", "nebula", Old Norse nifl.