Source : Webster's Revised Unabridged Dictionary (1913)

Lumbar \Lum"bar\, Lumbal \Lum"bal\, a. [L. lumbus loin. See
   {Loin}.] (Anat.)
   Of, pertaining to, or near, the loins; as, the lumbar
   arteries.

   {Lumbar region} (Anat.), the region of the loin;
      specifically, a region between the hypochondriac and ilias
      regions, and outside of the umbilical region.

Source : WordNet®

lumbar
     adj : of or relating to or near the part of the back between the
           ribs and the hipbones; "lumbar vertebrae"