International law is the body of rules established by custom or treaty and recognized by nations as binding in their relations with one another.
The term "international law" refers to public international law, governing the relationship between states and international entities.
It includes these legal fields:
international criminal law
law of the sea,
the laws of war
international humanitarian law and
international human rights law.
Private international law deals with which jurisdiction and which laws apply in the jurisdiction which may hear a case .
Supranational law applies to the regional agreements where the laws of nation states may be held inapplicable when in conflict with a supranational legal system where the nation involved has a treaty obligation.