The Collaborative International Dictionary of English v.0.48:

Rabdomancy \Rab"do*man`cy\ (r[a^]b"d[-o]*m[a^]n`s[y^]), n. [Gr.
   "ra`bdos rod + -mancy.]
   Divination by means of rods or wands. [Written also
   rhabdomancy.] --Sir T. Browne.
   [1913 Webster]