The Metaverse represents a paradigm shift in digital interaction, converging extended reality (XR), artificial intelligence (AI), blockchain technologies, and cloud-edge infrastructure to create persistent, immersive virtual environments. This comprehensive survey provides a systematic examination of the Metaverse's architectural foundations, cross-sector applications, and profound societal implications. We introduce a novel multi-dimensional taxonomy that organizes the Metaverse ecosystem along technical stacks (Interfaces, Intelligence, Trust \& Identity, Infrastructure) and socio-technical dimensions (Governance \& Standards, Safety \& Ethics, Human Factors). Our analysis reveals transformative opportunities across education, healthcare, industry, and entertainment sectors, while identifying critical challenges including biometric privacy, algorithmic bias, environmental sustainability, and digital fragmentation. The paper delineates substantial research gaps in longitudinal studies, ethical AI frameworks, and inclusive design practices. We propose a structured research agenda emphasizing interoperable standards, privacy-preserving architectures, sustainable infrastructure, and participatory governance models. This work provides scholars, practitioners, and policymakers with a comprehensive framework for navigating the complex landscape of Metaverse development and its societal ramifications.