"Singularity"
This is the term that mathematicians give to a point when an equation breaks down and ceases to have any useful meaning. The rules change. Something completely different happens.
A simple example of a singularity occurs if you try to divide a number by zero. If you divide by smaller and smaller numbers, the results will be larger and larger number. But if you divide a number by zero, you get infinity, which is not a number in the everyday sense. The equation has broken down.
The idea that there might be a singularity in human development was first suggested by mathematician Vernon Vinge and subsequently by others, most notably Ray Kurzweil in his book: The singularity is near.