Business requirements are high level requirements that management and a board of directors would typically understand, as follows:
Requirement 1: "We need to establish an online customer portal."
Requirement 2: "The portal should list our products." Functional requirements on the other hand are very detailed and outline exactly what needs to be delivered and would typically be read by business analysts, developers, project manager and testers: Requirement 3: "The system shall be able to register a product using the following fields: Name (20 characters long), Details (2000 characters long), Price (currency), Category (pick list)."
Requirement 4: "The system shall support that up to 5 pictures can be listed per product."
So it means that a business requirement (The portal should list our products) will be broken in to one or more detailed functional requirements as shown above. In addition you would have a section with user stories that details the different uses of the system step-by-step e.g.