Cyber defense refers to the strategies, technologies, and processes used to protect computers, networks, and data from unauthorized access, cyberattacks, and other digital threats. It involves proactive measures such as firewalls, antivirus software, intrusion detection systems, and employee training to prevent, detect, and respond to cyber incidents. Effective cyber defense helps organizations safeguard sensitive information, maintain business continuity, and reduce the risk of financial or reputational damage caused by cybercrime.