Is there any difference between cryptography and cryptology? Is there a difference between cryptography and cryptology, if any?

An internet search suggests that both terms can be used interchangeably.
Today, indeed the the terms "Cryptography" and "Cryptology" can mostly be used interchangeably. 

Historically things have been more interesting though, where Cryptology was the umbrella term for Cryptanalysis and (constructive) Cryptography. For example the Handbook of Applied Cryptography (chapter 1 PDF) has the following definition (page 15) of "Cryptology":


  Cryptology is the study of cryptography (Definition 1.1) and cryptanalysis.


with "Cryptanalysis" being defined as (on page 15)


  Cryptanalysis is the study of mathematical techniques for attempting
  to defeat cryptographic techniques, and, more generally, information
  security services.


and "Cryptography" being defined as (on page 4)


  Cryptography is the study of mathematical techniques related to
  aspects of information security such as confidentiality, data
  integrity, entity authentication, and data origin authentication.