Difference between the usage of 'on' and 'over' preposition
1. covering something; part of the surface
This definition tells us that on means that one thing is covering something else. It usually touches the surface. Sometimes it is part of the surface, like putting butter on the surface of toast.
• Most people put butter on their toast.
• Put your jacket on before you go outside.
• I wear my grandmother's ring on my left ring finger.
Over and above would not be used in place of on with this definition.
1. covering; on top of
This definition tells us that over means that one thing is covering or laying on the top of something else.
The definition is very similar to on. On is often used in place of over when it means “on top of.”
Over also suggests movement or covering a larger area, such as driving over a bridge.
• She is wearing a sundress over her swimsuit.
• We flew over the Grand Canyon. (Over would suggest movement from one side to the other.)
• Lay the blanket over his legs. (Lay the blanket on his legs.)
• I put my hand over her mouth to keep her quiet. (I put my hand on her mouth.)