Source : Webster's Revised Unabridged Dictionary (1913)

Therefore \There"fore\, conj. & adv. [OE. therfore. See {There},
   and {Fore}, adv., {For}, and cf. {Therefor}.]
   1. For that or this reason, referring to something previously
      stated; for that.

            I have married a wife, and therefore I can not come.
                                                  --Luke xiv.
                                                  20.

            Behold, we have forsaken all, and followed thee;
            what shall we have therefore?         --Matt. xix.
                                                  27.

   2. Consequently; by consequence.

            He blushes; therefore he is guilty.   --Spectator.

   Syn: See {Then}.

Source : WordNet®

therefore
     adv 1: (used to introduce a logical conclusion) from that fact or
            reason or as a result; "therefore X must be true";
            "the eggs were fresh and hence satisfactory"; "we were
            young and thence optimistic"; "it is late and thus we
            must go"; "the witness is biased and so cannot be
            trusted" [syn: {hence}, {thence}, {thus}]
     2: as a consequence; "he had good reason to be grateful for the
        opportunities which they had made available to him and
        which consequently led to the good position he now held"
        [syn: {consequently}]