Explain The Difference Between User Requirements And System Requirements?

From what I found in some website, it seems like user requirement is equal to the functional requirement while system requirement is equal to the non-functional requirement.

So, user requirement is what the user expect the system will look like while system requirement is what the system should do to satisfy the constraints and user's expectation.

For example, user want a teapot that can contain 500 ml of tea and it must be hot-proof, easy to carry and not easily broken (this is user requirement).
To create this teapot, we need to have high quality clay, certain degree to burn the shape, to make it strong, we need to burn it several times in 3 days, we need the table to shape the clay etc. (this is system requirement)

reference:
www.coleyconsulting.co.uk

*user requirement: Statement in natural language and diagrams for the service provide by the system. Written for customers.

*system requirement: A structured document setting out detailed of the system function. Defines what should be implemented. Written for software developers.