ECHO (Gr. I'Xw)  , in Greek mythology, one of the Oreades or mountain nymphs, the personification of the acoustical phenomenon known by this name . She was beloved by Pan, but rejected his advances . Thereupon the angry god drove the shepherds of the district mad; they tore Echo in pieces, and scattered her limbs broadcast, which still retained the gift of scng (Longus iii . 23) . According to Ovid (Metam. iii . 356-401), Echo by her incessant talking having prevented Juno from surprising Jupiter with the Nymphs, Juno changed her into an " echo "—a being who could not speak till she was spoken to, and then could only repeat the last words of the speaker . While in this condition she fell in love with Narcissus, and in grief at her unrequited affection wasted away until nothing remained but her voice and bones, which were changed into rocks . The legends of Echo are of late, probably Alexandrian, origin, and she is first personified in Euripides . In acoustics an " echo " is a return of sound from a reflecting surface (see SOUND: Reflection) . See F . Wieseler, Die Nymphe Echo (1854), and Narkissos (1856) ; P . Decharme in Daremberg and Saglio's Dictionnaire des antiquates .