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

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "ology":
   academic discipline, academic specialty, applied science, area,
   arena, art, concern, department of knowledge, discipline, domain,
   field, field of inquiry, field of study, natural science, province,
   pure science, science, social science, specialty, sphere, study,
   technicology, technics, technology