Terminal velocity

Definition

Consider an object moving through a fluid with an external force acting on it. The terminal velocity of the object relative to that external forcei s defined as a velocity that the object attains at which there is no net acceleration on the object. In other words, at a terminal velocity, the total drag force exerted on the object is equal and opposite to the external force.

The typical context in which this term is used is where the external force is the force of gravity and the object is falling downward.