most-favored-nation clause

from the GNU version of the Collaborative International Dictionary of English.

• (Diplomacy) A clause, often inserted in treaties, by which each of the contracting nations binds itself to grant to the other in certain stipulated matters the same terms as are then, or may be thereafter, granted to the nation which receives from it the most favorable terms in respect of those matters. It is used most frequently in treaties regarding the terms of trade between countries, as regarding tariffs and non-tariff barriers to trade.