What is the rate of change of displacement called?

Velocity:

1. The rate of change in displacement is referred to as velocity.
2. In general, the velocity of an object changes during its motion.
3. It is also called the first-order derivative of displacement with respect to time.
4. It can be expressed as $v=\frac{dx}{dt}$. Here $v$ is the velocity,$x$ is displacement and $t$ is time.