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: Webster's Revised Unabridged Dictionary (1913)