A machine-readable definition is a formal, structured description of a term that software can query, validate, and enforce. Instead of plain-language wording, the meaning is encoded in a format such as a schema, policy rule, ontology, or JSON object. This removes ambiguity and lets systems treat the definition as logic, not just documentation.
In cybersecurity, this matters because security controls depend on consistent meaning. A tool can only block sensitive data, classify assets, or trigger an alert correctly if it knows exactly what counts as “sensitive,” “critical,” or “privileged.” Attackers often exploit vague policy language and inconsistent labels across teams. Machine-readable definitions help defenses by making access rules, detection logic, and data handling policies executable, auditable, and harder to misinterpret by humans or AI agents.