What is the difference between a business requirement and a functional requirement?

A business requirement describes the requirements for the business e.g. better operational performance, higher booking through put, lower headcount.

Functional requirements describe a system will function e.g. click on button A to retrieve client info, click button C to generate a document etc.

I believe a business requirement is often confused with a functional requirement because a new system is often built to meet certain business requirements whereas the system itself will have its own functional requirements for its creation.