/ Dictionary / Index S steady state theory: Meaning and Definition of Find definitions for: stead'y state' the"ory Pronunciation: [key] — Astron. Astron. a theory in which the universe is assumed to have average properties that are constant in space and time so that new matter must be continuously and spontaneously created to maintain average densities as the universe expands. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. steady-handed steak Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language