The terms treaty, pact, charter, constitution,
statute, convention, General Act, Final Act (when
it is an independent instrument) are generally used
for formal instruments of multilateral character.
The terms such as memorandum of understanding,
procés vérbal, arrangement, exchange of notes are
used for less formal instruments and generally
related to transactions of provisional or temporary
nature. The terms like declarations, agreements,
modus vivendi or joint communiqué are common
to both formal and less formal types of agreements.