1. The act or instance of giving one thing and receiving another in its place. 2. To give and receive reciprocally; interchange. 3. A place or network for exchanging things, especially a center where securities or commodities are bought and sold. 4. A system of payments using instruments, such as negotiable drafts, instead of money. 5. A bill or rate of exchange. 6. The amount of difference in the actual value of two or more currencies or between values of the same currency at two or more places. 7. A dialogue between two or more people.