- cyber attack - malicious use of information systems in order to influence the information, systems, processes, actions or decisions of the target without their consent,
- cyber conflict - a confrontation between two or more parties, where at least one party uses cyber attacks against the other(s),
- cyber war - a cyber conflict between state actors, where the critical information infrastructure is attacked,
- cyber terrorism - a cyber conflict where one party is using cyber attacks to cause fear, physical damage, and/or death among the civilian population of the other party.
I am sure these definitions will change as my understanding of the topic grows.