What is an example of ontology?

Could you elaborate on what constitutes an "ontology" in the realm of cryptocurrencies and finance? Specifically, I'm seeking a concrete example to aid in my understanding. An ontology, in a general sense, refers to the classification and relationships between entities within a specific domain. However, in the context of cryptocurrencies and finance, how might an ontology be defined and applied? Is there a particular framework or methodology you could share as an example? Your clarification would be greatly appreciated.