The Collaborative International Dictionary of English v.0.48:

Pelvis \Pel"vis\, n. [L., a basin, laver; cf. Gr. ?, ?, bowl.]
   1. (Anat.) The pelvic arch, or the pelvic arch together with
      the sacrum. See Pelvic arch, under Pelvic, and
      Sacrum.
      [1913 Webster]

   2. (Zool.) The calyx of a crinoid.
      [1913 Webster]

   Pelvis of the kidney (Anat.), the basinlike cavity into
      which the ureter expands as it joins the kidney.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pelvis
    n 1: the structure of the vertebrate skeleton supporting the
         lower limbs in humans and the hind limbs or corresponding
         parts in other vertebrates [syn: pelvis, pelvic girdle,
         pelvic arch, hip]
    2: a structure shaped like a funnel in the outlet of the kidney
       into which urine is discharged before passing into the ureter
       [syn: pelvis, renal pelvis]