I lift a block of mass $m$ by a height $h$ in gravitational field. I have done a work of $mgh$ on the block. This energy is stored in the block when it is at height $h$. At height $h$, the block has got some energy that was given to it, by the virtue of which it has a potential to do work. Hence that energy is called potential energy.
Now consider that the block moves with some velocity $v$. When the block is moving it has some energy and by the virtue of that energy the block could still do work (it may collide with a spring and compress it). Then why do we not call this type of energy which is possessed during motion potential energy as well?
I mean 'kinetic energy' has also got the potential to do work, then why it's called kinetic energy?