From the Overview: "The Department of Defense (DOD) defines cyberspace as a global domain within the information environment consisting of the interdependent network of information technology infrastructures and resident data, including the internet, telecommunications networks, computer systems, and embedded processors and controllers. The DOD Information Network (DODIN) is a global infrastructure carrying DOD, national security, and related intelligence community information and intelligence. Cyberspace operations are composed of the military, intelligence, and ordinary business operations of the DOD in and through cyberspace. Military cyberspace operations use cyberspace capabilities to create effects that support operations across the physical domains and cyberspace. Cyberspace operations differ from information operations (IO), which are specifically concerned with the use of information-related capabilities during military operations to affect the decision making of adversaries while protecting our own. IO may use cyberspace as a medium, but it may also employ capabilities from the physical domains."
CRS In Focus, IF10537
Congressional Research Service: https://crsreports.congress.gov/