Difference between build and release

What is the difference between build and release?

A “build” is given by dev team to the test team. A “release” is formal release of the product to its customers.
A build when tested and certified by the test team is given to the customers as “release”. A “build” can be rejected by test team if any of the tests fail or it does not meet certain requirements. One release can have several builds associated with it.

How do you differentiate the roles of Quality Assurance Manager and Project Manager?

Quality Assurance Manager (QA Manager) defines the process to be followed at each phase of SDLC. He defines the standards to be followed, the documents to be maintained and sets the standard for the product.
Where as it is the Project Manager’s responsibility to ensure that the things defined by QA manager are being implemented. He develops the product from start to finish with his team and ensures that the product which is to be rolled out is Defect free and it reaches the standards and views defined by QA Manager.
QA managers can audit the process for certain time periods which are being handled by the Project Manager.