The term that refers to the speed at which a falling object stops accelerating and begins to fall at a constant rate is terminal velocity.

Here's why:

* Acceleration due to gravity: When an object falls, it accelerates downwards due to gravity.

* Air resistance: As the object falls faster, it encounters more air resistance. This force opposes the force of gravity.

* Terminal velocity: At some point, the force of air resistance becomes equal to the force of gravity. At this point, the object stops accelerating and falls at a constant speed, which is called terminal velocity.

Let me know if you have any other questions!