Source : Webster's Revised Unabridged Dictionary (1913)

Echo \Ech"o\, n.; pl. {Echoes}. [L. echo, Gr. ? echo.] (Whist)
   (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.

Echo \Ech"o\, n.; pl. {Echoes}. [L. echo, Gr. ? echo, sound,
   akin to ?, ?, sound, noise; cf. Skr. v[=a]? 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.

            The babbling echo mocks the hounds.   --Shak.

            The woods shall answer, and the echo ring. --Pope.

   2. Fig.: Sympathetic recognition; response; answer.

            Fame is the echo of actions, resounding them.
                                                  --Fuller.

            Many kind, and sincere speeches found an echo in his
            heart.                                --R. L.
                                                  Stevenson.

   3.
      (a) (Myth. & Poetic) A wood or mountain nymph, regarded as
          repeating, and causing the reverberation of them.

                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.

                Compelled me to awake the courteous Echo To give
                me answer from her mossy couch.   --Milton.

   {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      superseded by the swell.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.

            I would applaud thee to the very echo, That should
            applaud again.                        --Shak.

Echo \Ech"o\, v. i.
   To give an echo; to resound; to be sounded back; as, the hall
   echoed with acclamations. ``Echoing noise.'' --Blackmore.

Echo \Ech"o\, v. t. [imp. & p. p. {Echoed}; p. pr. & vb. n.
   {Echoing}. -- 3d pers. sing. pres. {Echoes}.]
   1. To send back (a sound); to repeat in sound; to
      reverberate.

            Those peals are echoed by the Trojan throng.
                                                  --Dryden.

            The wondrous sound Is echoed on forever. --Keble.

   2. To repeat with assent; to respond; to adopt.

            They would have echoed the praises of the men whom
            they ?nvied, and then have sent to the newspaper
            anonymous libels upon them.           --Macaulay.

Source : WordNet®

echo
     n 1: the persistence of a sound after its source has stopped
          [syn: {reverberation}, {sound reflection}, {replication}]
     2: (Greek mythology) a nymph who was spurned by Narcissus and
        pined away until only her voice remained
     3: a reply that repeats what has just been said
     [also: {echoes} (pl)]

echo
     v 1: to say again or imitate; "followers echoing the cries of
          their leaders" [syn: {repeat}]
     2: ring or echo with sound; "the hall resounded with laughter"
        [syn: {resound}, {ring}, {reverberate}]
     3: call to mind; "His words echoed John F. Kennedy" [syn: {recall}]
     [also: {echoes} (pl)]

Source : Free On-Line Dictionary of Computing

echo
     
        1. A {topic group} on {FidoNet}'s {echomail} system.
     
        Compare {newsgroup}.
     
        2. A {Unix} command that just prints its arguments.
     
        [{Jargon File}]