Learning is an experience-driven, long term, relational process which results in a change in how we interact with the environment due to the information we have come into contact with.
Learning is when a system can use the information it has seen in the past to infer general rules about other information in the future. Learning is not memorizing.
Learning = generalize, infer, analogize (building analogies for different situations), adaptive (if the environment changes then you don't break down).
Learning is always a change. If you don't change you probably have not learned a lot. The change manifests itself in a long-lasting change with how the system interacts with the environment.