Maybe “single design principle” or “abstraction principle”? (I have for a while felt that abstraction at the class level is very much overrated, while abstract

Maybe “single design principle” or “abstraction principle”? (I have for a while felt that abstraction at the class level is very much overrated, while abstraction at the system level tends to be glossed over. This has lead me to enjoy building systems with microservices. Because the interfaces tend to be dictated by the external systems that use the service, but the guts of a service can and do change dramatically.)