nebulas

noun pl. nebulae or nebulas

1. a cloud of interstellar gas or dust: formerly, applied to any hazy, distant celestial object, as a star cluster or an external galaxy
2. 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