In Uniform Circular Motion velocity is not constant due to continuous change in Direction and thus, it is not a uniform motion.
This type of motion is defined as the motion of an object in which the object travels in a straight line and its velocity remains constant along that line as it covers equal distances in equal intervals of time, irrespective of the duration of the time.
Uniform circular motion
The movement of a body following a circular path is called a circular motion. Now, the motion of a body moving with constant speed along a circular path is called Uniform Circular Motion. Here, the speed is constant but the velocity changes.
So if a particle is moving in a uniform circular motion:
1) Its speed is constant
2) Velocity is changing at every instant
3) There is no tangential acceleration