Source : Webster's Revised Unabridged Dictionary (1913)

Cryptology \Cryp*tol"o*gy\ (kr?p-t?l"?-j?), n. [Gr. krypto`s
   hidden + -logy.]
   Secret or enigmatical language. --Johnson.

Source : WordNet®

cryptology
     n : the science of analyzing and deciphering codes and ciphers
         and cryptograms [syn: {cryptanalysis}, {cryptanalytics},
         {cryptography}]

Source : Free On-Line Dictionary of Computing

cryptology
     
        The study of {cryptography} and {cryptanalysis}.
     
        (1994-12-06)