The term marketing channel is often used interchangeably with “sales channel” or “distribution channel”, i.e. any individual or company used in making the subject company's products and/or services available to its customers. More specifically, a marketing channel would be any individuals or products through which the subject company conducts its marketing efforts.
A Marketing Channel performs the work of moving goods from producers to consumers. It overcomes the time place and possession gaps that separate goods and services from those who need or want them. It involves all the transactions that happen between the parties, all from the supplier on the 'bottom' and the customer at the 'top'.