Source : Webster's Revised Unabridged Dictionary (1913)

Aston \As*ton"\, Astone \As*tone"\, v. t. [imp. & p. p.
   {Astoned}, {Astond}, or {Astound}.] [See {Astonish}.]
   To stun; to astonish; to stupefy. [Obs.] --Chaucer.

Astound \As*tound"\, v. t. [imp. & p. p. {Astounded}, [Obs.]
   {Astound}; p. pr. & vb. n. {Astounding}.] [See {Astound}, a.]
   1. To stun; to stupefy.

            No puissant stroke his senses once astound.
                                                  --Fairfax.

   2. To astonish; to strike with amazement; to confound with
      wonder, surprise, or fear.

            These thoughts may startle well, but not astound The
            virtuous mind.                        --Milton.

Astound \As*tound"\, v. t. [imp. & p. p. {Astounded}, [Obs.]
   {Astound}; p. pr. & vb. n. {Astounding}.] [See {Astound}, a.]
   1. To stun; to stupefy.

            No puissant stroke his senses once astound.
                                                  --Fairfax.

   2. To astonish; to strike with amazement; to confound with
      wonder, surprise, or fear.

            These thoughts may startle well, but not astound The
            virtuous mind.                        --Milton.

Astound \As*tound"\, a. [OE. astouned, astound, astoned, p. p.
   of astone. See {Astone}.]
   Stunned; astounded; astonished. [Archaic] --Spenser.

         Thus Ellen, dizzy and astound. As sudden ruin yawned
         around.                                  --Sir W.
                                                  Scott.

Source : WordNet®

astound
     v : affect with wonder; "Your ability to speak six languages
         amazes me!" [syn: {amaze}, {astonish}]