Onandontoare prepositions.
We useonwhen we refer to a position on a surface (on the table, on the ocean, on the moon, on the roof, on the bus):
Your keys areonthe table.
The men were standingonthe roof.
We useontoto talk about direction or movement to a position on a surface, usually with a verb that expresses movement:
The cat climbedontothe roof.
She emptied the suitcase full of clothesontothe floor.
We useonto describe a position along a road or river or by the sea or by a lake:
The hotel isonthe road opposite the beach.
They have a fabulous houseona lake in Ireland.
We useontoto describe movement towards an end position along a road or river:
The path leadsontothe main road.
We useonorontowith very little difference in meaning to refer to attachment or movement of something to something else.Ontogives a stronger feeling of movement:
There’s a battery pack with the camera that you can clipontoa belt.
You can save the dataontoyour hard disk.
Have you put the picturesonyour memory stick?
See also:
At,onandin(place)
At,onandin(time)