Source : Webster's Revised Unabridged Dictionary (1913)

Alter \Al"ter\, v. t. [imp. & p. p. {Altered}; p. pr. & vb. n.
   {Altering}.] [F. alt['e]rer, LL. alterare, fr. L. alter
   other, alius other. Cf. {Else}, {Other}.]
   1. To make otherwise; to change in some respect, either
      partially or wholly; to vary; to modify. ``To alter the
      king's course.'' ``To alter the condition of a man.'' ``No
      power in Venice can alter a decree.'' --Shak.

            It gilds all objects, but it alters none. --Pope.

            My covenant will I not break, nor alter the thing
            that is gone out of my lips.          --Ps. lxxxix.
                                                  34.

   2. To agitate; to affect mentally. [Obs.] --Milton.

   3. To geld. [Colloq.]

   Syn: {Change}, {Alter}.

   Usage: Change is generic and the stronger term. It may
          express a loss of identity, or the substitution of one
          thing in place of another; alter commonly expresses a
          partial change, or a change in form or details without
          destroying identity.

Source : WordNet®

altered
     adj 1: changed in form or character without becoming something
            else; "the altered policy promised success";
            "following an altered course we soon found ourselves
            back in civilization"; "he looked...with couded eyes
            and with an altered manner of breathing"- Charles
            Dickens [ant: {unaltered}]
     2: having testicles or ovaries removed [syn: {neutered}]
     3: changed in order to improve or made more fit for a
        particular purpose; "seeds precisely adapted to the area";
        "instructions altered to suit the children's different
        ages" [syn: {adapted}]