means A point at which the usual rules break down because some quantity becomes infinite or undefined — whether the crushing center of a black hole, a glitch in a mathematical function, or the hypothesized moment when machine intelligence surpasses human control and accelerates beyond prediction.

from From Latin 'singularis,' meaning single, alone, or one of a kind — itself from 'singulus,' separate or individual. It entered English meaning simply 'uniqueness' or 'oddness.' Mathematicians and physicists later borrowed it for points where equations misbehave, and in the 20th century it became the name for the unfathomable heart of a black hole. The technological sense — a runaway intelligence explosion — was popularized in the late 20th century by mathematician and writer Vernor Vinge, who borrowed the physics image deliberately: a horizon past which we cannot see.