Displacement and instantaneous:
Displacement is the distance vector that the object has displaced from its initial position. It is calculated from the starting point to the endpoint in the journey of the object in question. The displacement can be understood as the straight line joining the points mentioned above. Keep in mind that the actual path taken by the object is not related to the displacement. The exact route is the average distance.
Velocity is the speed in a particular direction. If I say the speed of the car was 10mph than it would be speed, but if I say the speed was 10mph in the right direction than it would be velocity. So, the Directional speed is velocity. Velocity is a vector quantity and follows the rules of vector algebra and cannot be added or subtracted. The notation of velocity is a v with an arrow on the top. The arrow just tells that the quantity in question is a vector.
