revision vs. version

In my experience, revision is more of an internal term that matches up with the unique identifier of a check-in or build. Version is a label of a released product so that you know whether the version is newer or not than what you have.

In my view, versions are used when the configuration item features are different or more than the previous one. While revisions is the number of times that you find error and fix in the same version i.e., functionalities remains same but the errors are fixed.