Definitions of Settlement Commission clarify who qualifies as assessee and the scope of pending applications for settlement. Section 31 defines key terms for settlement proceedings: assessee (broadly including liable persons, producers, manufacturers, registered persons and private warehouses), case (proceedings for levy, assessment and collection of excise duty pending before an adjudicating authority, excluding proceedings remitted for fresh adjudication), institutional roles (Bench, Chairman, Vice-Chairman, Member), Commissioner (Investigation), an Interim Board, and a limited definition of pending application with specified filing and allowance conditions.