1. Trade , commerce , traffic refer to the exchanging of commodities for other commodities or money. Trade is the general word: a brisk trade between the nations. Commerce applies to trade on a large scale and over an extensive area: international commerce. Traffic may refer to a particular kind of trade; but it usually suggests the travel, transportation, and activity associated with or incident to trade: the opium traffic; heavy traffic on the railroads. 6. See occupation. 14. Trade , bargain , barter , sell refer to exchange or transfer of ownership for some kind of material consideration. Trade conveys the general idea, but often means to exchange articles of more or less even value: to trade with Argentina. Bargain suggests a somewhat extended period of coming to terms: to bargain about the price of a horse. Barter applies especially to exchanging goods, wares, labor, etc., with no transfer of money for the transaction: to barter wheat for machinery. Sell implies transferring ownership, usually for a sum of money: to sell a car.

Did you mean trade down?