AI Takeoff refers to the process of an Artificial General Intelligence going from a certain threshold of capability (often discussed as "human-level") to being super-intelligent and capable enough to control the fate of civilization. There has been much debate about whether AI takeoff is more likely to be slow vs fast, i.e., "soft" vs "hard".
See also: AI Timelines, Seed AI, Singularity, Intelligence explosion, Recursive self-improvement
AI takeoff is sometimes casually referred to as AI FOOM....