A specification of security controls, control enhancements, supplemental guidance, and other supporting information employed during the tailoring process, that is intended to complement (and further…

An overlay is a defined set of security controls, control enhancements, and other guidance that refines a security control baseline for specific communities of interest, technologies, or environments. This tailoring mechanism allows an organization to customize the baseline controls to be more specific or stringent for their particular context while still leveraging the original baseline structure.

Safeguards are general protective measures, not a specific process or document for tailoring security baselines.

A baseline is the initial set of security controls for a system, which an overlay complements and refines, rather than being the refining mechanism itself.

Feature is a generic term that does not describe a formal security documentation or tailoring process.