1. A group of countries that levy lower (or zero) tariffs against imports from members than outsiders. Includes FTAs, customs unions, and common markets. Encouragement to use this term instead of the more misleading FTA has come from Jagdish Bhagwati, as in Bhagwati and Panagariya (1996). 2. Frankel (1997) uses PTA for an arrangement where internal tariffs are reduced but not zero, reserving FTA for a trading bloc with zero internal tariffs.