Digital currency exchangers (a.k.a. DCEs or Bitcoin exchanges), businesses that allow customers to trade digital currencies for other assets, such as conventional fiat money, or different digital currencies
Trade, the exchange of goods or services for money or other goods or services
Post exchange (a.k.a. "PX" or base exchange), a retail store operated by Army and Air Force Exchange Service on US military installations worldwide; originally akin to trading posts, they now resemble contemporary department stores or strip malls.