The C4 model for visualising software architecture

The book The C4 model for visualising software architecture goes over how we should divide the language we use based on the level of granularity we are trying to explain and that we should never mix those levels in a conversation. By using a common vocabulary we can leave better documentation behind us and improve onboarding. It proposes a starting point of 4 levels: Context, Container, Component and Code but since projects can defer in scope it also provides alternatives.