CableLabs CableLabs This document defines the core vocabulary, comparison model, and extension discipline used by Privacy Preference Declarations (PPDs) to express atomic privacy-relevant dataflows in home networks. It complements the companion PPD architecture and protocol work by standardizing the core fields used in participant declarations and household policy rules. The core vocabulary is the mandatory shared semantic floor for baseline participant-facing interoperability. Richer ecosystem-specific vocabularies remain possible, but comparison-relevant non-core terms need explicit relationships to the shared core so they remain computable. Baseline participant-facing protocol messages use compact identifiers plus taxonomy context rather than requiring full ontology exchange on the wire.