/ Dictionary / Index C companion star: Meaning and Definition of Find definitions for: compan'ion star" Pronunciation: [key] — Astron. Astron. companion (def. 6). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. companionship companionway Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language