Occurrence or change of a particular set of circumstances.
Source(s):
NIST SP 800-160 Vol. 1 from ISO Guide 73

  Any observable occurrence in a network or system.
Source(s):
CNSSI 4009-2015 from NIST SP 800-61 Rev. 2
NIST SP 800-61 Rev. 2 under Event

  Something that occurs within a system or network.
Source(s):
NIST SP 800-92 under Event

  Any observable occurrence in a network or information system.
Source(s):
NIST SP 800-37 Rev. 2

  Any observable occurrence in a system.
Source(s):
NIST SP 800-53 Rev. 5 from NIST SP 800-61 Rev. 2 - Adapted

  Any observable occurrence on a manufacturing system. Events can include cybersecurity changes that may have an impact on manufacturing operations (including mission, capabilities, or reputation).
Source(s):
NISTIR 8183 under Event from NIST Cybersecurity Framework Version 1.1, NIST Cybersecurity Framework Version 1.0
NISTIR 8183 Rev. 1 under Event from NIST Cybersecurity Framework Version 1.1
NISTIR 8183A Vol. 1 under Event from NIST Cybersecurity Framework Version 1.1
NISTIR 8183A Vol. 2 under Event from NIST Cybersecurity Framework Version 1.1
NISTIR 8183A Vol. 3 under Event from NIST Cybersecurity Framework Version 1.1

  Any observable occurrence in an information system.
Source(s):
NIST SP 800-53 Rev. 4 [Superseded] under Event from CNSSI 4009 - Adapted