meaning the machine can use
Models are fluent in language and blind to meaning. This is the layer where meaning gets made explicit: the ontology that says what exists and how it relates, and the semantic model and knowledge graph that turn raw data into something a machine can reason over rather than merely retrieve. Get this wrong and everything above inherits the confusion. Get it right and the rest gets easier than it has any right to be.
The high-level components of this layer.
OntologyA more complete view of this layer is in progress.