Human-readable information
affixed to information system components, removable media, or output indicating
the distribution limitations, handling caveats and applicable security
markings. [NIST-SP800-53:2013]
Human-readable indicators
applied to a document, storage media, or hardware component to designate
security classification, categorization and/or handling restrictions applicable
to the information contained therein. For intelligence information, these could
include compartment and sub-compartment indicators and handling restrictions. [CNSSI_4009:2010]