The standard for project management

Requirements Management Plan.

 A component of the project or program management plan that describes how 

requirements will be analyzed, documented, and managed.

Requirements Traceability Matrix. 

A grid that links product requirements from their origin to the deliverables that 

satisfy them.

Reserve. 

A provision in the project management plan to mitigate cost and/or schedule risk. Often used with a modifier 

(e.g., management reserve, contingency reserve) to provide further detail on what types of risk are meant to be mitigated.