Terror is usually described as the feeling of dread and anticipation that precedes the horrifying experience. By contrast, horror is the feeling of revulsion that usually follows a frightening sight, sound, or otherwise experience.
Terror seeks to evoke by suggestion, by dreadful suspense; horror displays in the hopes of generating revulsion. Terror veils a potentially ghastly unknown and tempts the reader to advance cautiously and with anticipation, while marches the reader through a landscape of unmistakable taboo and atrocity.