System and assets, whether physical or virtual, so vital to the United States that the incapacity or destruction of such systems and assets would have a debilitating impact on security, national economic security, national public health or safety, or any combination of those matters.
Source(s):
NIST SP 800-30 Rev. 1 under Critical Infrastructure

  Systems and assets, whether physical or virtual, so vital to the United States that the incapacity or destruction of such systems and assets would have a debilitating impact on security, national economic security, national public health or safety, or any combination of those matters.
Source(s):
NIST SP 800-53 Rev. 5 from PL 107-56 (Patriot Act)

  Essential services and related assets that underpin American society and serve as the backbone of the nation's economy, security, and health.
Source(s):
NISTIR 8183 under Critical Infrastructure from DHS - Unknown Source, National Cybersecurity & Communications Integration Center
NISTIR 8183 Rev. 1 under Critical Infrastructure from DHS
NISTIR 8183A Vol. 1 under Critical Infrastructure from DHS
NISTIR 8183A Vol. 2 under Critical Infrastructure from DHS
NISTIR 8183A Vol. 3 under Critical Infrastructure from DHS

  Systems and assets, whether physical or virtual, so vital to the United States that the incapacity or destruction of such systems and assets would have a debilitating impact on cybersecurity, national economic security, national public health or safety, or any combination of those matters.
Source(s):
NIST Cybersecurity Framework Version 1.1 under Critical Infrastructure

  System and assets, whether physical or virtual, so vital to the U.S. that the incapacity or destruction of such systems and assets would have a debilitating impact on security, national economic security, national public health or safety, or any combination of those matters.
Source(s):
CNSSI 4009-2015 [Superseded]