nymph on Mount Helicon sentenced (forgive the word-play) by Hera to speak only when she was spoken to, and even then merely to repeat the final syllables uttered by another. She loved Narcissus, who spurned her - or according to another story was loved in vain by Pan.
All in all, a frustrating life. Her name, of course, means what it says, although originally the Greek word (echo) meant 'sound', 'noise'. Let us perhaps compromise, and call her 'The Resounder'.