Source : Webster's Revised Unabridged Dictionary (1913)

Emotion \E*mo"tion\, n. [L. emovere, emotum, to remove, shake,
   stir up; e out + movere to move: cf. F. ['e]motion. See
   {Move}, and cf. {Emmove}.]
   A moving of the mind or soul; excitement of the feelings,
   whether pleasing or painful; disturbance or agitation of mind
   caused by a specific exciting cause and manifested by some
   sensible effect on the body.

         How different the emotions between departure and
         return!                                  --W. Irving.

         Some vague emotion of delight.           --Tennyson.

   Syn: Feeling; agitation; tremor; trepidation; perturbation;
        passion; excitement.

   Usage: {Emotion}, {Feeling}, {Agitation}. Feeling is the
          weaker term, and may be of the body or the mind.
          Emotion is of the mind alone, being the excited action
          of some inward susceptibility or feeling; as, an
          emotion of pity, terror, etc. Agitation may the bodily
          or mental, and usually arises in the latter case from
          a vehement struggle between contending desires or
          emotions. See {Passion}. ``Agitations have but one
          character, viz., that of violence; emotions vary with
          the objects that awaken them. There are emotions
          either of tenderness or anger, either gentle or
          strong, either painful or pleasing.'' --Crabb.

Source : WordNet®

emotion
     n : any strong feeling