From Citizendium, the Citizens' Compendium
- International law : The formal conduct of interactions between nation-states, both at the national level and on behalf of their citizens; generally accepted as first formalized by Hugo Grotius.
- International humanitarian law : That part of international law concerned with minimizing the human consequences of conventional and unconventional armed conflict
- Just war theory : The branch of ethics concerned with the basis for starting, conducting, and terminating wars
- Hostis humani generis : A legal principle that certain acts, such as piracy, slavery and genocide, puts one outside the norms of civilization and makes one an "enemy of all mankind", subject to early forms of universal jurisdiction or summary action