Reverse engineering applies to many industries, for both software and hardware. Software written to work only with one microprocessor or operating system can be reverse-engineered and remade to work with a different processor or OS. Malware often uses reverse-engineered code as a disguise, and cybersecurity often reverse-engineers malware to fight it.
The biomedical field reverse engineers proteins, organs, DNA, and more to study their functions. Notably, the Human Genome Project used reverse engineering to sequence human DNA.
Design and manufacturing use reverse engineering for many things, including large-scale projects like appliances, computers, and even vehicles, such as the Soviet MiG-25 “Foxbat” fighter jet, which was reverse-engineered after a Russian pilot defected and landed in Japan.