- A symbol is an atomic expression or syntactic constituent that may be used in axioms. (Moreover, an semantic interpretation or model of an ontology usually consists of an interpretation of all the symbols.)
- Symbols have different kinds, for example, in OWL, there a classes, object properties, individuals etc. (In other logics, there are other kinds of symbols.) For each symbol, there is a tab displaying the symbols of that kind.
kind, there is a
- A sentence (formula) is a logical expression constraining the meaning (interpretation) of the ontology and often thereby linking different symbols.
- A sentence may be an axiom (i.e. it is postulated to be true) a conjecture (i.e. it is postulated to follow from the axioms), or a theorem (i.e. it has been proven to follow from the axioms).