The Collaborative International Dictionary of English v.0.48:

Ology \Ol"o*gy\, n. [See -logy.]
   A colloquial or humorous name for any science or branch of
   knowledge.
   [1913 Webster]

         He had a smattering of mechanics, of physiology,
         geology, mineralogy, and all other ologies whatsoever.
                                                  --De Quincey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ology
    n 1: an informal word (abstracted from words with this ending)
         for some unidentified branch of knowledge