A test case is a one which checks functionality of one particular object at a time..A scenario can check functionality of multiple objects and we can tell this as one business process.We can define a series of test-case executed as one scenario. A test case is the procedure followed to execute a test, it consists of the details about the input and expected result.
Test scenarios are based on a hypothetical story to help a person to think through a complex program or a system.Think of a scenario as a workflow. It tests a series of test cases .
Definition of test suite:
A collection of test scenarios and/or test cases that are related or that may cooperate with each other.