Meaning of panspermia

pan•sper•mi•a

Pronunciation: (pan-spûr'mē-u), [key]
— n. Biol.
  1. the theory that life exists and is distributed throughout the universe in the form of germs or spores that develop in the right environment.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.