In 15 U.S.C. §1127:
1) The exchanging, buying, or selling of things having economic value between two or more entities, for example goods, services, and money. Commerce is often done on a large scale, typically between individuals, businesses, or nations.
2) The Lanham Act (trademark) provides that a mark is all be deemed to be in "use in commerce"
(1) on goods when:
(A) it is placed in any manner on the goods or their containers or the displays associated therewith or on the tags or labels affixed thereto, or if the nature of the goods makes such placement impracticable, then on documents associated with the goods or their sale, and
(B) the goods are sold or transported in commerce, and
(2) on services when it is used or displayed in the sale or advertising of services and the services are rendered in commerce, or the services are rendered in more than one State or in the United States and a foreign country and the person rendering the services is engaged in commerce in connection with the services.