Abstract
RDFS and OWL ontologies simultaneously define naming, hierarchy, syntactical data structure, and axioms. This strong coupling complicates the reusability of both ontological concepts and annotated data, due to logical pitfalls in RDFS and OWL semantics. The differences between OWL axioms and integrity constraints used for validation are often not clear to users and lead to confusing and unintended semantics in practice. To avoid these pitfalls, we revisit Tom Gruber's basic ontology definition and reimagine a more decoupled ontology design pattern, consisting of independent layers for naming, validation, and reasoning. We argue that such decoupling improves reusability because it clarifies the usage of the three layers during ontology creation and reuse. A naming layer built on synonym sets enables reusing named concepts in different contexts, detached from constraints or OWL axioms defined elsewhere. On top of that, we suggest a two-step approach of constraint checking and reasoning: Validate a term's integrity via constraints first, and only include it for reasoning if that validation succeeds. Our proposal is one step towards a clearer in-practice usage of naming, validation, and reasoning-and additionally supports this with a revised semantic layer model.