  Growth in computational materials science and initiatives such as the
Materials Genome Initiative (MGI) and the European Materials Modelling Council
(EMMC) has motivated the development and application of ontologies. A key
factor has been increased adoption of the FAIR principles, making research data
findable, accessible, interoperable, and reusable (Wilkinson et al. 2016). This
paper characterizes semantic interoperability among a subset of materials
science ontologies in the MatPortal repository. Background context covers
semantic interoperability, ontological commitment, and the materials science
ontology landscape. The research focused on MatPortal's two interoperability
protocols: LOOM term matching and URI matching. Results report the degree of
overlap and demonstrate the different types of ambiguity among ontologies. The
discussion considers implications for FAIR and AI, and the conclusion highlight
key findings and next steps.
