The Cross-domain Interoperability Framework (CDIF) provides a semantic foundation for enabling Semantic Croissant across diverse research domains. CDIF defines a common, extensible knowledge graph model that harmonizes dataset structures, variables, and metadata using shared concepts and controlled vocabularies. By aligning Croissant descriptions with CDIF, datasets become machine-interpretable, domain-agnostic, and interoperable, supporting seamless integration across repositories, disciplines, and AI workflows. This approach strengthens FAIR compliance and enables scalable reuse of research data within EOSC and beyond.