Separation of Concerns
A bit of a buzz concept.
When specialities were separate(ish) this did often lead to interaction via defined APIs (as teams would work to an API be they the API producer or consumer), and so e.g. a UI could easily be ported to a new backend as long as appropriate APIs written bt the team working on the new backend
WiIth agile / multi skilled approach, SoC need to be continually hammered into peoples mind sets as, without team separation, SoC no longer happens by default