We know that the linear displacement, velocity and acceleration are vector quantities. Similarly, angular quantities like angular displacement, angular velocity and angular acceleration are also vectors. To express them completely, we need to mention their definite directions along with their magnitudes. By convention, the directions of these vector quantities are taken along the axis of rotation.
Vectors like displacement, linear velocity, linear acceleration, linear momentum, and force have real directions. These are known as polar vectors. The initial point of any polar vector is known as the pole of the vector.
The direction of the vectors associated with rotational motion like angular displacement, angular velocity and angular acceleration, etc is imagined to be along a real axis, which is nothing but the axis of rotation. These vectors are axial vectors.