- Board / BSP: one physical product and its wiring, descriptor, startup and electrical preparation. Apps do not infer hardware from board IDs.
- Platform / HAL: processor-family implementation and bounded peripheral primitives. K210 SDK details stay here rather than in apps.
- Driver: implementation for a device or peripheral. It does not own app workflows.
- Service: reusable behavior with explicit lifetimes, errors and cleanup. Only service headers intentionally published by the SDK are external APIs.
- Capability: the historical directory name for the public typed Time, Input, Lights, Display and External Link services; it does not imply a broker.
- Binding: immutable selected implementation of a typed service.
- Session: stable caller-owned storage for a resource claim. Open sessions cannot be copied or moved. Conflicts and quarantine are service-local.
- Borrow: temporary access to an existing buffer or workspace. Its lifetime ends at the documented release or terminal operation; it is not an allocation.
- Runtime: foreground app lifecycle, ordered dispatch, bounded state and resource cleanup. Context generations reject stale app work.
- App: statically composed feature with its own state and policy. Bundled apps may use permitted portable firmware services; standalone apps use the SDK.
- Adapter: maps a service to another client surface, such as MicroPython, preserving resource lifetimes and deadlines without duplicating hardware logic.
- Experimental: a usable interface that can evolve through documented version changes; explicit compatibility requirements still apply.
In specifications, MUST and MUST NOT describe required behavior; SHOULD describes a default with a reasoned exception; MAY describes optional behavior.