Classified information or classified national security information means information that has been determined pursuant to E. O. 12958 as amended by E.O. 13292 or any predecessor order to require protection against unauthorized disclosure and is marked to indicate its classified status when in documentary form.
Source(s):
NIST SP 800-59 under Classified Information from E.O. 13292

  See classified national security information.
Source(s):
CNSSI 4009-2015
NIST SP 800-37 Rev. 2

  Information that has been determined: (i) pursuant to Executive Order 12958 as amended by Executive Order 13526, or any predecessor Order, to be classified national security information; or (ii) pursuant to the Atomic Energy Act of 1954, as amended, to be Restricted Data (RD).
Source(s):
NIST SP 800-53 Rev. 4 under Classified Information

  Information that has been determined pursuant to Executive Order (E.O.) 13292 or any predecessor order to require protection against unauthorized disclosure and is marked to indicate its classified status when in documentary form.
Source(s):
NIST SP 800-60 Vol. 1 Rev. 1 under Classified Information
NIST SP 800-60 Vol. 2 Rev. 1 under Classified Information