"Megacorporation" is a term popularize by William Gibson derived from the combination of the prefix mega- with the word corporation. It has become a term popularly used in cyberpunk literature. It refers to a corporation that is a massive conglomerate, holding monopolistic or near-monopolistic control over multiple markets (thus, it exhibits both horizontal and vertical monopoly). Megacorps are so powerful that they can ignore the law, possess their own heavily-armed (often military-sized) private army, hold 'sovereign' territory, and possibly even act as an outright government. They often exercise a large degree of control over their employees, with the idea of 'corporate culture' taken to an extreme.