Distribution channel tells the medium by which products and services are distributed by an organization to its end users. Division in an organizational structure represents a product or service line in a single organization.
A Sales area is known as entity which is required to process an order in a company. It is comprised of Sales organization, distribution channel and a division.
In SAP SD organizational structure, each sales organization is assigned to a company code. Distribution channel and divisions are assigned to Sales organization and all comprise to make a sales area.