[1][2][3][4] Courts are permanent bodies, with near the same composition for each case.
Arbitral tribunals, by contrast, are constituted anew for each case.
Both courts and arbitral tribunals can make binding decisions.
Quasi-judicial institutions, by contrast, make rulings on cases, but these rulings are not in themselves legally binding; the main example is the individual complaints mechanisms available under the various UN human rights treaties.
It does not include mere proposed institutions for which no instrument was ever signed.