The Collaborative International Dictionary of English v.0.48:

Torrid \Tor"rid\, a. [L. torridus, fr. torrere to parch, to
   burn, akin to E. Thist: cf. F. torride. See Thirst.]
   1. Parched; dried with heat; as, a torrid plain or desert.
      "Barca or Cyrene's torrid soil." --Milton.
      [1913 Webster]

   2. Violenty hot; drying or scorching with heat; burning;
      parching. "Torrid heat." --Milton.
      [1913 Webster]

   Torrid zone (Geog.), that space or board belt of the earth,
      included between the tropics, over which the sun is
      vertical at some period of every year, and the heat is
      always great.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Torrid Zone
    n 1: the part of the Earth's surface between the Tropic of
         Cancer and the Tropic of Capricorn; characterized by a hot
         climate [syn: Torrid Zone, tropical zone, tropics]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "Torrid Zone":
   Antarctic Zone, Arctic Circle, Arctic Zone, Frigid Zones,
   Tropic of Cancer, Tropic of Capricorn, Variable Zones, climate,
   clime, equator, furnace, hell, horse latitudes, inferno, latitude,
   longitude, longitude in arc, meridian, oven, parallel,
   prime meridian, roaring forties, steam bath, subtropics, the line,
   tropic, tropics, zone