Okay yep I will try to explain better.
Previously I have worked with json schema where you can specify a parent ontology term so that any child term is considered a valid value for that property, and use json schema validation to validate them as child terms. This means that essentially all child terms of a parent term form an enum, without having to explicitly define them as an enum within the schema. This also means that you don't need to know 'upfront' the exact terms you want as part of the enum, only that the terms will come from a specific ontology or branch of ontology. Additionally, as the ontology changes, there is no need to update the underlying schema by adding/removing enums.
Going back to my example of defining a property for a 'part of organism', it would be somewhat simpler to say, we recognise the all the anatomical terms in the UBERON ontology, rather than having to specify upfront 10s-100s of ontology terms and link each one to an enum value. This of course has other trade-offs in terms of maybe allowing too many terms.
I was just curious as to whether this kind of functionality existed, but as I understand it from your answer, any ontology terms that we would want to use as values for a property would need to be specified explicitly, one-by-one as enums.