In the context of sales & marketing, "the Channel" is the chain of organizations that a product must pass through before a customer can buy it. The Channel is also called by many other names such as 'distribution network', 'supply chain' or simply as 'trade'.
It's best understood with an example:
A product is usually made by a brand* at a factory. The brand then sells this product to a national distributor which sells it to a state level distributor which sells it to a retailer which sells it to a customer. This is an example of a Retail Channel. Even within a retail channel, many variations are possible. In the Organized Retail business, brands may directly sell to the retailer. In other combinations - brands may sell to regional distributors, not national distributors. Regional distributors may sell to city distributors, not state distributors, and so on.
Other examples of channels are:
- E-Commerce Channel
- Door-to-Door Channel
- B2B Channel etc.
* : The term brand is used generically. In cases of commodity or generic products - the product is made by a non-brand manufacturer.