This book is a pioneering reference work designed to address the complex terminology, technical specifications, and diverse applications of valves in industrial systems. The Comprehensive Valve Dictionary: Terminology, Applications, and Insights for Oil, Gas, and Renewable Energy is an authoritative and practical reference that demystifies the technical language surrounding industrial valves. The dictionary provides detailed definitions for hundreds of valve-related terms, including valve types, components, materials, standards, testing methods, and failure mechanisms. In addition to traditional applications, this dictionary places significant emphasis on valves used in renewable energy systems, including those for hydrogen production, hydropower, carbon capture and storage (CCS), geothermal energy, and offshore wind power. Moreover, it explores the definitions and real-world applications of cutting-edge technologies such as smart valves, condition monitoring, digital twin technology, and additive manufacturing. It also includes cross-references to relevant international standards (e.g., API, ASME, ISO), troubleshooting guides, and operational insights. By bridging gaps in understanding, this resource will support professionals in making informed decisions, improving system reliability, and ensuring compliance with industry best practices. This work is specifically tailored for engineers, designers, manufacturers, and researchers working in oil and gas, petrochemicals, power generation, and renewable energy industries.