The definition of self propelled is something that moves, progresses or acts on its own power without needing outside help.
An example of self propelled is a lawnmower that draws from its own power to go up hills and to move along the grass.
propelled by its own motor or power
- Containing its own means of propulsion: a self-propelled golf cart.
- Fired from or mounted on a moving vehicle: a self-propelled howitzer.
- Having its own means of propulsion that moves with it.