A predetermined set of instructions or procedures that describe how an organization’s mission-essential functions will be sustained within 12 hours and for up to 30 days as a result of a disaster event before returning to normal operations.
Sources:
CNSSI 4009-2015 under continuity of operations plan (COOP) from NIST SP 800-34 Rev. 1

  2. A written plan for recovering one or more information systems at an alternate facility in response to a major hardware or software failure or destruction of facilities.
Sources:
CNSSI 4009-2015 from NIST SP 800-34 Rev. 1

  Management policy and procedures used to guide an enterprise response to a perceived loss of mission capability. The Contingency Plan is the first plan used by the enterprise risk managers to determine what happened, why, and what to do. It may point to the continuity of operations plan (COOP) or disaster recovery plan (DRP) for major disruptions.
Sources:
CNSSI 4009-2015 under contingency plan

  Management policy and procedures used to guide an enterprise response to a major loss of enterprise capability or damage to its facilities. The DRP is the second plan needed by the enterprise risk managers and is used when the enterprise must recover (at its original facilities) from a loss of capability over a period of hours or days.
Sources:
CNSSI 4009-2015

  A written plan for recovering one or more information systems at an alternate facility in response to a major hardware or software failure or destruction of facilities.
Sources:
NIST SP 800-34 Rev. 1 under Disaster Recovery Plan (DRP)

  A written plan for processing critical applications in the event of a major hardware or software failure or destruction of facilities.
Sources:
NIST SP 800-82r3 under Disaster Recovery Plan from NIST SP 800-34 Rev. 1 - adapted