The main difference is that speed is a "scalar" quantity ... it only has size.
Velocity is a "vector" quantity ... it has size AND a direction.
Velocity is a vector quantity, which means that a body's speed and direction are both required to define it. They are different because: Speed is the rate of change of distance with time
but velocity is the rate of change of displacement with time.
6.0m questions
7.8m answers