/ Dictionary / Index C cosmic noise: Meaning and Definition of Find definitions for: cos'mic noise' Pronunciation: [key] radio-frequency noise that originates outside the earth's atmosphere. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. cosmic dust cosmic ray Related Content Daily Word Quiz: digression Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language