Source : Webster's Revised Unabridged Dictionary (1913)

Horror \Hor"ror\, n. [Formerly written horrour.] [L. horror, fr.
   horrere to bristle, to shiver, to tremble with cold or dread,
   to be dreadful or terrible; cf. Skr. h?sh to bristle.]
   1. A bristling up; a rising into roughness; tumultuous
      movement. [Archaic]

            Such fresh horror as you see driven through the
            wrinkled waves.                       --Chapman.

   2. A shaking, shivering, or shuddering, as in the cold fit
      which precedes a fever; in old medical writings, a chill
      of less severity than a rigor, and more marked than an
      algor.

   3. A painful emotion of fear, dread, and abhorrence; a
      shuddering with terror and detestation; the feeling
      inspired by something frightful and shocking.

            How could this, in the sight of heaven, without
            horrors of conscience be uttered?     --Milton.

   4. That which excites horror or dread, or is horrible; gloom;
      dreariness.

            Breathes a browner horror on the woods. --Pope.

   {The horrors}, delirium tremens. [Colloq.]

Source : WordNet®

horror
     n 1: intense and profound fear
     2: something that inspires horror; something horrible; "the
        painting that others found so beautiful was a horror to
        him"
     3: intense aversion [syn: {repugnance}, {repulsion}, {revulsion}]