/ Dictionary / Index P permanent echo: Meaning and Definition of Find definitions for: per'manent ech'o Pronunciation: [key] — Electronics. Electronics. a radar signal reflected to a radar station on the ground by a building or other fixed object. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Permanent Court of International Justice permanent lens Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language