The Collaborative International Dictionary of English v.0.48:

Tor \Tor\, n. [AS. torr; cf. Gael. torr. Cf. Tower.]
   [1913 Webster]
   1. A tower; a turret. [R.] --Ray.
      [1913 Webster]

   2. High-pointed hill; a rocky pinnacle. [Prov. Eng.]
      [1913 Webster]

            A rolling range of dreary moors, unbroken by tor or
            tree.                                 --C. Kingsley.
      [1913 Webster] Torace

WordNet (r) 3.0 (2006):

tor
    n 1: a prominent rock or pile of rocks on a hill
    2: a high rocky hill

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "tor":
   Everest, Olympus, alp, crest, hilltop, hump, knoll,
   lofty mountains, lofty peak, mount, mountain, mountaintop, peak,
   pic, pico, pike, pinnacle, point, precipice, spur, summit,
   the wooded mountains, towering alps