Command and control is a “set of organizational and technical attributes and processes … [that] employs human, physical, and information resources to solve problems and accomplish missions” to achieve the goals of an organization or enterprise, according to a 2015 definition by military scientists Marius Vassiliou, David S. Alberts, and Jonathan R. Agre. The term often refers to a military system.

Versions of the United States Army Field Manual 3-0 circulated circa 1999 define C2 in a military organization as the exercise of authority and direction by a properly designated commanding officer over assigned and attached forces in the accomplishment of a mission.

A 1988 NATO definition is that command and control is the exercise of authority and direction by a properly designated individual over assigned resources in the accomplishment of a common goal. An Australian Defense Force definition, similar to that of NATO, emphasizes that C2 is the system empowering designated personnel to exercise lawful authority and direction over assigned forces for the accomplishment of missions and tasks.(The Australian doctrine goes on to state: The use of agreed terminology and definitions is fundamental to any C2 system and the development of joint doctrine and procedures. The definitions in the following paragraphs have some agreement internationally, although not every potential ally will use the terms with exactly the same meaning.)

US perspective

The US Department of Defense Dictionary of Military and Associated Terms defines command and control as: “The exercise of authority and direction by a properly designated commander over assigned and attached forces in the accomplishment of the mission. Also called C2.

The edition of the Dictionary “As Amended Through April 2010” elaborates, “Command and control functions are performed through an arrangement of personnel, equipment, communications, facilities, and procedures employed by a commander in planning, directing, coordinating, and controlling forces and operations in the accomplishment of the mission.” However, this sentence is missing from the “command and control” entry for the edition “As Amended Through 15 August 2014.”

Commanding officers are assisted in executing these tasks by specialized staff officers and enlisted personnel. These military staff are a group of officers and enlisted personnel that provides a bi-directional flow of information between a commanding officer and subordinate military units.

The purpose of a military staff is mainly that of providing accurate, timely information which by category represents information on which command decisions are based. The key application is that of decisions that effectively manage unit resources. While information flow toward the commander is a priority, information that is useful or contingent in nature is communicated to lower staffs and units.

Computer security industry

This term is also in common use within the computer security industry and in the context of cyber-warfare. Here the term refers to the influence an attacker has over a compromised computer system that they control. For example, a valid usage of the term is to say that attackers use “command and control infrastructure” to issue “command and control instructions” to their victims. Advanced analysis of command and control methodologies can be used to identify attackers, associate attacks, and disrupt ongoing malicious activity.

Derivative terms

There are a plethora of derivative terms which emphasis different aspects, uses and sub-domains of C2. These terms come with a plethora of associated abbreviations – for example, in addition to C2, command and control is also often abbreviated as C2, and sometimes as C&C.
Embraer R-99 MULTI INTEL, an example of aircraft with C3I capabilities

Command and control have been coupled with :

Communication / communications
(Military) intelligence
Information / information systems
Computers / computing
Target acquisition
Electronic warfare

and others.

Some of the more common variations include:

C2I – Command, control & intelligence
C2I – command, control & information (a less common usage)
R2C2I – rapid advanced manufacturing, command, control & intelligence [developed by SICDRONE]
C2IS – command and control information systems
C2ISR – C2I plus surveillance and reconnaissance
C2ISTAR – C2 plus ISTAR (intelligence, surveillance, target acquisition, and reconnaissance)
C3 – command, control & communication (human activity focus)
C3 – command, control & communications (technology focus)
C3 – consultation, command, and control [NATO]
C3I – 4 possibilities; the most common is command, control, communications and intelligence
C3ISREW – C2ISR plus communications plus electronic warfare (technology focus)
C3MS – cyber command and control mission system
C3/SA – C3 plus situational awareness
C4, C4I, C4ISR, C4ISTAR, C4ISREW, C4ISTAREW – plus computers (technology focus) or computing (human activity focus)
C4I2 – command, control, communications, computers, intelligence, and interoperability
C5I – command, control, communications, computers, collaboration and intelligence
C6ISR – command, control, communications, computers, cyber-defense and combat systems and intelligence, surveillance, and reconnaissance
MDC2 – multi-domain command and control
NC2 − nuclear command and control
NC3 − nuclear command and control and communications

and others.

Command: The exercise of authority based upon certain knowledge to attain an objective.
Control: The process of verifying and correcting activity such that the objective or goal of command is accomplished.
Communication: Ability to exercise the necessary liaison to exercise effective command between tactical or strategic units to command.
Computers: The computer systems and compatibility of computer systems. Also includes data processing.
Intelligence: Includes collection as well as analysis and distribution of information.