Definition of step-on:
(n) :
An advance or movement made from one foot to the other; a pace.
(n) :
A rest, or one of a set of rests, for the foot in ascending or descending, as a stair, or a rung of a ladder.
(n) :
The part of a spade, digging stick or similar tool that a digger's foot rests against and presses on when digging; an ear, a foot-rest.
(n) :
(glassblowing) The button joining a glass's stem to its foot.
(n) :
A distinct part of a process; stage; phase.
(n) :
A running board where passengers step to get on and off the bus.