This document provides a detailed definition and analysis of "input services" under the CENVAT Credit Rules, 2004. It begins by defining input services as any service used in manufacturing or providing an output service. It then analyzes the definition in three parts - the main definition, an inclusive list of additional services, and exclusions. The analysis examines each part in depth, providing examples and exceptions. It aims to comprehensively explain the scope and coverage of input services eligible for CENVAT credit.