The exchange of commodities for commodities. Considered in a legal point of view, it consists in the various agreements which have for their object to facilitate the exchange of the products of the earth or industry of man, with an intent to realize a profit.
In a narrower sense, commerce signifies any reciprocal agreements between two persons by which one delivers to the other a thing, which the latter accepts and for which he pays a consideration. If the consideration be money, it is called a sale; if any other thing than money, it is called exchange or barter.
The U.S. Congress has power by the Constitution to regulate commerce with foreign nations, among the several states and with the Indian tribes. The sense in which the word commerce is used in the Constitution seems not only to include traffic, but intercourse and navigation.