There are multiple definitions - click on the translation that matches your context.
treaty means:
Abkommen means:
Substantiv
partial
noun
Usually, this English term is more formally translated into German as "Staatsvertrag", but informally it is often simply referred to as an "Abkommen", so that translating Abkommen into treaty is likely the best choice in most contexts.
an agreement between two or more independent nations
The question of the way in which income earned in a foreign country is to be taxed in the home country is regulated by a tax treaty between the two countries.