Inbound adapters: handle requests from the outside by invoking the business logic
Outbound adapters: invoked by the business logic and invoke external applications
Port: defines a set of operations and is how the business logic interacts with what’s outside of it
inbound port: an API exposed by the business logic, which enables it to be invoked by external applications. Ex. service interface / service public method
outbound port: how the business logic invokes external systems. ex. repository interface, which defines a collection of data access operations