Tangible scientific samples are the cornerstone of experimental research across all disciplines. Yet they are described and documented in myriad ways, often using highly specialised metadata and standards. The Sample Type Classification Working Group (WG) is developing a high-level, cross-domain vocabulary to categorise samples – broad enough to span research fields, yet structured enough to guide the selection of appropriate metadata frameworks.The goal is not to replace domain-specific ontologies, but rather to link sample types to existing metadata schema, enabling more consistent annotation, improved interoperability, and enhanced data discovery.To ensure the vocabulary reflects the full diversity of scientific practice, we invite input from data experts in every domain. Whether you manage an ontology, curate sample data, or contribute to community standards – or simply know what metadata your own samples require – your insights can help define your domain’s region of the broader sample universe.This poster outlines the WG’s scope, vision, and opportunities for engagement. Help us build a shared language for samples that supports FAIR principles and unlocks more effective data sharing and reuse across science.

On display at International Data Week 2025 through the Research Data Alliance (RDA), this poster outlines the purpose of the new RDA Sample Classification Working Group (WG) and requests input from the wider community. The WG aims to produce a top-level sample classification vocabulary, and needs input from all research domains to achieve this.