Capability Map
A structured view of everything a business does, used as the stable frame for mapping applications, investment, ownership and gaps.
The map is deliberately implementation-free: it names capabilities ("Order Management", "Claims Adjudication", "Customer Onboarding"), not systems, teams or processes. That is what lets it stay stable while everything underneath changes.
What it is actually used for, in order of value: overlaying the application portfolio, which immediately reveals duplication (five systems doing one capability) and gaps (a capability with no system); heat-mapping by business criticality against technical health, which is how modernisation is prioritised on evidence rather than by whoever complains loudest; and assigning ownership to something that will still exist after the next reorganisation.
Keep it to two or three levels. The failure mode is decomposing to five levels and producing an artefact so large that nobody maintains it, at which point it becomes confidently wrong.