Megacorporation, mega-corporation, or megacorp, a term popularized by William Gibson, derives from the combination of the prefix mega- with the word corporation. It has become widespread in cyberpunk literature. It refers to a corporation (normally fictional) that is a massive conglomerate (usually private), holding monopolistic or near-monopolistic control over multiple markets (thus exhibiting both a horizontal and a vertical monopoly). Megacorps are so powerful that they can ignore the law, possess their own heavily armed (often military-sized) private armies, be the operator of a privatized police force, hold "sovereign" territory, and even act as outright governments. They often exercise a large degree of control over their employees, taking the idea of "corporate culture" to an extre