/ Dictionary / Index N nebular hypothesis: Meaning and Definition of Find definitions for: neb'ular hypoth'esis Pronunciation: [key] — Astron. Astron. the theory that the solar system evolved from a mass of nebular matter: prominent in the 19th century following its precise formulation by Laplace. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. nebula nebulated Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language