FOMI is an international forum where academic researchers and industrial practitioners meet to analyse and discuss application issues related to methods, theories, tools and applications based on formal ontologies. There is today wide agreement that knowledge modelling and the semantic dimension of information play an increasingly central role in networked economy: semantic-based applications aim to provide a framework for information and knowledge sharing, reliable information exchange, meaning negotiation and coordination between distinct organizations or among members of the same organization.

Theoretical ideas seem often very promising but their actual implementation brings up unexpected problems and issues. The FOMI 2021 Workshop aims to collect useful experiences and lessons learned by the presentation of:

1. Experience with problems in ontology application.
2. New insights on known problematic issues.
3. New results.
4. Successes and observations in ontology implementation.
5. Lessons learned on the best way to apply ontological methodologies to real-world situations.

FOMI 2021 will facilitate open discussion and experience sharing. Very similar problems arise in disparate ontology applications and an open discussion helps to highlight commonalities and to spread ideas for possible solutions. For this reason, FOMI welcomes researchers and practitioners that embrace this perspective without restrictions on the domains they deal with: business, medicine, engineering, finance, law, biology, geography, electronics, etc.