From the Document: "Electronic warfare (EW), as defined by the Department of Defense (DOD), are military activities that use electromagnetic energy to control the electromagnetic spectrum ('the spectrum') and attack an enemy. The spectrum is a range of frequencies for electromagnetic energy. EW supports command and control (C2) by allowing military commanders' access to the spectrum to communicate with forces, while preventing potential adversaries from accessing the spectrum to develop an operational picture and communicate with their forces. Some have argued that EW is a component of anti-access/area denial (A2/AD) campaigns."
CRS In Focus, IF11118
Congressional Research Service: https://crsreports.congress.gov/