Commerce: The exchange of goods and services, esp. on a large scale involving transportation between cities, states and nations.

Interstate Commerce: Trade and other business activities between those located in different states; esp. traffic in goods and travel of people between states.

Intrastate Commerce: Commerce that begins and ends entirely within the borders of a single state

Commercial Law:   The substantive law dealing with the sale of goods, the financing of credit transactions on the security of the goods sold, and negotiable instruments.  *Most American commercial law is governed by the Uniform Commercial  Code. — Also termed mercantile law