Source : Webster's Revised Unabridged Dictionary (1913)

Interested \In"ter*est*ed\, a. [See {Interest}, v. t.]
   1. Having the attention engaged; having emotion or passion
      excited; as, an interested listener.

   2. Having an interest; concerned in a cause or in
      consequences; liable to be affected or prejudiced; as, an
      interested witness.

Interest \In"ter*est\, v. t. [imp. & p. p. {Interested}; p. pr.
   & vb. n. {Interesting}.] [From interess'd, p. p. of the older
   form interess, fr. F. int['e]resser, L. interesse. See
   {Interest}, n.]
   1. To engage the attention of; to awaken interest in; to
      excite emotion or passion in, in behalf of a person or
      thing; as, the subject did not interest him; to interest
      one in charitable work.

            To love our native country . . . to be interested in
            its concerns is natural to all men.   --Dryden.

            A goddess who used to interest herself in marriages.
                                                  --Addison.

   2. To be concerned with or engaged in; to affect; to concern;
      to excite; -- often used impersonally. [Obs.]

            Or rather, gracious sir, Create me to this glory,
            since my cause Doth interest this fair quarrel.
                                                  --Ford.

   3. To cause or permit to share. [Obs.]

            The mystical communion of all faithful men is such
            as maketh every one to be interested in those
            precious blessings which any one of them receiveth
            at God's hands.                       --Hooker.

   Syn: To concern; excite; attract; entertain; engage; occupy;
        hold.

Source : WordNet®

interested
     adj 1: having or showing interest; especially curiosity or
            fascination or concern; "an interested audience";
            "interested in sports"; "was interested to hear about
            her family"; "interested in knowing who was on the
            telephone"; "interested spectators" [ant: {uninterested}]
     2: involved in or affected by or having a claim to or share in;
        "a memorandum to those concerned"; "an enterprise in which
        three men are concerned"; "factors concerned in the rise
        and fall of epidemics"; "the interested parties met to
        discuss the business" [syn: {concerned}]