'Echo organ' definitions:

Definition of 'Echo organ'

From: GCIDE

Echo \Ech"o\ ([e^]k"[-o]), n.; pl. Echoes ([e^]k"[=o]z). [L. echo, Gr. 'hchw` echo, sound, akin to 'hchh`, 'h^chos, sound, noise; cf. Skr. v[=a][,c] to sound, bellow; perh. akin to E. voice: cf. F. ['e]cho.]
1. A sound reflected from an opposing surface and repeated to the ear of a listener; repercussion of sound; repetition of a sound. [1913 Webster]
The babbling echo mocks the hounds. --Shak. [1913 Webster]
The woods shall answer, and the echo ring. --Pope. [1913 Webster]
2. Fig.: Sympathetic recognition; response; answer. [1913 Webster]
Fame is the echo of actions, resounding them. --Fuller. [1913 Webster]
Many kind, and sincere speeches found an echo in his heart. --R. L. Stevenson. [1913 Webster]
3. (a) (Myth. & Poetic) A wood or mountain nymph, regarded as repeating, and causing the reverberation of them. [1913 Webster]
Sweet Echo, sweetest nymph, that liv'st unseen Within thy airy shell. --Milton. (b) (Gr. Myth.) A nymph, the daughter of Air and Earth, who, for love of Narcissus, pined away until nothing was left of her but her voice. [1913 Webster]
Compelled me to awake the courteous Echo To give me answer from her mossy couch. --Milton. [1913 Webster]
4. (Whist, Contract Bridge) (a) A signal, played in the same manner as a trump signal, made by a player who holds four or more trumps (or as played by some exactly three trumps) and whose partner has led trumps or signaled for trumps. (b) A signal showing the number held of a plain suit when a high card in that suit is led by one's partner. [Webster 1913 Suppl.]
Echo organ (Mus.), a set organ pipes inclosed in a box so as to produce a soft, distant effect; -- generally superseded by the swell.
Echo stop (Mus.), a stop upon a harpsichord contrived for producing the soft effect of distant sound.
To applaud to the echo, to give loud and continuous applause. --M. Arnold. [1913 Webster]
I would applaud thee to the very echo, That should applaud again. --Shak. [1913 Webster]