Black Holes and the Penrose-Hawking Singularity Theorem

The boundary beyond which nothing, not even light, can escape from the black hole.

The region inside the black hole where spacetime is curved to such an extent that it becomes a singularity.

The boundary beyond which the gravitational pull of the black hole becomes so strong that it can pull in even light.

The region outside the black hole where spacetime is curved but not to the extent that it becomes a singularity.