GATT stands for the General Agreement on Tariffs and Trade. From 1947 until 1995 it was the main world deal — and the club of countries around that deal — for making trade between countries easier: lowering taxes on imported goods (tariffs) and cutting rules that blocked trade. By the end, about eighty countries belonged, though the number grew over the years. In 1995 a new body with a similar job, the World Trade Organization (WTO), took over, and GATT as that club of countries stopped. Though actually, the old GATT text did not all vanish; some of its trade rules still sit inside the WTO system. You will meet GATT in history and economics, not in everyday talk. People say it as one word, like “gat,” not letter by letter.