The Collaborative International Dictionary of English v.0.48:

Sound \Sound\, a. [Compar. Sounder; superl. Soundest.] [OE.
   sound, AS. sund; akin to D. gezond, G. gesund, OHG. gisunt,
   Dan. & Sw. sund, and perhaps to L. sanus. Cf. Sane.]
   1. Whole; unbroken; unharmed; free from flaw, defect, or
      decay; perfect of the kind; as, sound timber; sound fruit;
      a sound tooth; a sound ship.
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   2. Healthy; not diseased; not being in a morbid state; --
      said of body or mind; as, a sound body; a sound
      constitution; a sound understanding.
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   3. Firm; strong; safe.
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            The brasswork here, how rich it is in beams,
            And how, besides, it makes the whole house sound.
                                                  --Chapman.
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   4. Free from error; correct; right; honest; true; faithful;
      orthodox; -- said of persons; as, a sound lawyer; a sound
      thinker.
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            Do not I know you a favorer
            Of this new seat? Ye are nor sound.   --Shak.
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   5. Founded in truth or right; supported by justice; not to be
      overthrown on refuted; not fallacious; as, sound argument
      or reasoning; a sound objection; sound doctrine; sound
      principles.
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            Hold fast the form of sound words, which thou hast
            heard of me.                          --2 Tim. i.
                                                  13.
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   6. heavy; laid on with force; as, a sound beating.
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   7. Undisturbed; deep; profound; as, sound sleep.
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   8. Founded in law; legal; valid; not defective; as, a sound
      title to land.
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   Note: Sound is sometimes used in the formation of
         self-explaining compounds; as, sound-headed,
         sound-hearted, sound-timbered, etc.
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   Sound currency (Com.), a currency whose actual value is the
      same as its nominal value; a currency which does not
      deteriorate or depreciate or fluctuate in comparision with
      the standard of values.
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The Collaborative International Dictionary of English v.0.48:

Sounder \Sound"er\, n.
   One who, or that which; sounds; specifically, an instrument
   used in telegraphy in place of a register, the communications
   being read by sound.
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The Collaborative International Dictionary of English v.0.48:

Sounder \Sound"er\, n. (Zool.)
   A herd of wild hogs.
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WordNet (r) 3.0 (2006):

sounder
    n 1: a device for making soundings

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "sounder":
   TelAutography, Teletype, Teletype network, Teletyping, barometer,
   closed-circuit telegraphy, code, duplex telegraphy, electricity,
   facsimile telegraph, feeler, interrupter, key,
   multiplex telegraphy, news ticker, pilot balloon, probe,
   quadruplex telegraphy, railroad telegraphy, random sample,
   receiver, sample, sender, simplex telegraphy,
   single-current telegraphy, sound, stock ticker, straw vote,
   submarine telegraphy, telegraphics, telegraphy, teleprinter,
   teletypewriter, teletypewriting, telex, ticker, transmitter,
   trial balloon, typotelegraph, typotelegraphy, weather vane,
   weathercock, wire service