nebula

noun3

1. •
   A cloud in outer space consisting of gas or dust (e.g. a cloud formed after a star explodes).

   • Approximately 5 billion years ago, our solar nebula was formed as gravitational forces pulled interstellar gas and dust into a swirling mass around out newly formed sun. — 2012
2. •
   (no longer used) A white spot or slight opacity of the cornea.
3. •
   (no longer used) A cloudy appearance in the urine.