Malware, short for malicious software, refers to any software or code specifically designed to disrupt, damage, or gain unauthorized access to computer systems, networks, or devices. It encompasses a wide range of malicious programs, including viruses, worms, Trojans, ransomware, spyware, and adware, which can cause various harmful effects such as data theft, system corruption, financial loss, and privacy breaches.

Example: A user unknowingly downloads a file that contains a virus. This virus spreads across their system, corrupting files and stealing sensitive information.