The Collaborative International Dictionary of English v.0.48:

Orology \O*rol"o*gy\, n. [Gr. 'o`ros mountain + -logy: cf. F.
   orologie.]
   The science or description of mountains.
   [1913 Webster]

WordNet (r) 3.0 (2006):

orology
    n 1: the science of mountains [syn: orology, orography]