The Collaborative International Dictionary of English v.0.48:

Varanus \Va*ra"nus\, prop. n. [NL., fr. Ar. uaran, uaral; cf. F.
   varan, from the Arabic.] (Zool.)
   A genus of very large lizards native of Asia and Africa. It
   includes the monitors. See Monitor, 3.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Varanus
    n 1: type and sole extant genus of the Varanidae [syn:
         Varanus, genus Varanus]