Wordnet 3.0
NOUN (1)
1. 
 either side of the backbone between the hipbone and the ribs in humans as well as quadrupeds; 
[syn: loin, lumbus]
WordNet (r) 3.0 (2006):
lumbus
    n 1: either side of the backbone between the hipbone and the
         ribs in humans as well as quadrupeds [syn: loin,
         lumbus]