Question

what is initial velocity

Answer 1

the velocity experienced by an object in its initial position...
for eg. the initial velocity of an falling object is 0
u=0
it is denoted by the letter u

Answer 2

Velocity is the rate that the position of an object changes relative to time. Forces acting on an object cause it to accelerate. This acceleration changes the velocity. The initial velocity,vi is the velocity of the object before acceleration causes a change.