The "point of no return" at a black hole is known as the event horizon. This boundary marks the region where the gravitational pull is so strong that nothing, not even light, can escape its grasp. Once an object crosses the event horizon, it is inevitably pulled into the black hole's singularity at its center.

The event horizon plays a crucial role in defining the characteristics of a black hole, such as its size and mass. It is a fascinating concept in astrophysics that highlights the extreme nature of these mysterious cosmic entities.