The Collaborative International Dictionary of English v.0.48:

Uro- \U"ro-\
   A combining form fr. Gr. o'y^ron, urine.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Uro- \U"ro-\
   A combining form from Gr. o'yra`, the tail, the caudal
   extremity.
   [1913 Webster]