The word "barter" does not have a direct equivalent in the context of the Roman Empire. The Romans used the term "permutatio" to refer to the exchange of goods or services without the use of money. This type of exchange was common in ancient Rome, especially in rural areas where money was scarce. Barter was also used in trade with foreign merchants who did not use the Roman currency. In urban areas, the Romans used a monetary system based on coins, and barter was less common.