The Collaborative International Dictionary of English v.0.48:

Iconology \I`co*nol"o*gy\, n. [Gr. ?; e'ikw`n an image + ?
   discourse: cf. F. iconologie.]
   The discussion or description of portraiture or of
   representative images. Cf. Iconography.
   [1913 Webster]

WordNet (r) 3.0 (2006):

iconology
    n 1: the branch of art history that studies visual images and
         their symbolic meaning (especially in social or political
         terms)

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "iconology":
   allegory, charactery, cipher, conventional symbol, emblem,
   ideogram, logogram, logotype, love knot, pictogram, symbol,
   symbolic system, symbolism, symbolization, symbology, token, totem,
   totem pole, type