Answer:
A singularity is originally a mathematical term for a point at which an equation has no solution. In physics, it was proven that a large enough collapsing star would eventually become a black hole, so dense that its own gravity would cause a 'singularity' in the fabric of space-time, a point where many of the physics equations suddenly have no solution.
Singularity has become, in physics, another name for a black hole, a compression of matter so dense, not even light can escape it.