The Collaborative International Dictionary of English v.0.48:

Torus \To"rus\ (t[=o]"r[u^]s), n.; pl. Tori (t[=o]"r[imac]).
   [L., a round, swelling, or bulging place, an elevation. Cf.
   3d Tore.]
   [1913 Webster]
   1. (Arch.) A large molding used in the bases of columns. Its
      profile is semicircular. See Illust. of Molding.
      --Brande & C.
      [1913 Webster]

   2. (Zool.) One of the ventral parapodia of tubicolous
      annelids. It usually has the form of an oblong thickening
      or elevation of the integument with rows of uncini or
      hooks along the center. See Illust. under Tubicolae.
      [1913 Webster]

   3. (Bot.) The receptacle, or part of the flower on which the
      carpels stand.
      [1913 Webster]

   4. (Geom.)
      (a) The surface described by the circumference of a circle
          revolving about a straight line in its own plane.
      (b) The solid inclosed by such a surface; -- sometimes
          called an anchor ring.

   Syn: Syn. --3d Tore[2].
        [1913 Webster]

WordNet (r) 3.0 (2006):

torus
    n 1: a ring-shaped surface generated by rotating a circle around
         an axis that does not intersect the circle [syn: torus,
         toroid]
    2: commonly the lowest molding at the base of a column [syn:
       torus, tore]