In English you have 'above', 'on', 'over' and 'on top of' but in Italian one word, 'sopra', covers all four meanings

Solution 1:

above at a high level ORIGIN Old English abufan (as an adverb), from a- ‘on’ + bufan (from bi ‘by’ + ufan ‘above’).

on physically in contact with (but also at a high level) ORIGIN Old English on, an, of Germanic origin; related to Dutch aan and German an, from an Indo-European root shared by Greek ana .

over at a high level same as above) or beyond (ORIGIN Old English ofer, of Germanic origin; related to Dutch over and German über, from an Indo-European word (originally a comparative of the element represented by -ove in above) which is also the base of Latin super and Greek huper .

on top of this is showing or identify that something is highest in the order of other things.

on top of 1 on the highest point or uppermost surface of: a town perched on top of a hill. • so as to cover; over: trays stacked one on top of another. • in close proximity to: we all lived on top of each other. 2 in command or control of: he couldn't get on top of his work. 3 in addition to: on top of everything else, he's a brilliant linguist.

(same Apple dictionary source)

Could over be similar to sopra? in application rather than meaning? overuse, overcoat, overseen, overhead, overhaul, overhand, overflow

There seems to be an English obsession (historical) with this desire of knowing where something is in relation to other things. Think on the reason why this and that code for proximity. Why is that important? short answer, we don't know.

etymology from Apple dictionary (Version 2.2.3 (118.5). Holmes (2001:329 -An Introduction to Sociolinguistics) raises this question on this v that and proximity...and why it seems important to code for it.

Solution 2:

Need is an odd word to use. Does English need four words here? No, as Italian apparently does not, but as an English speaker I can spot plenty of points of confusion. Does English need plurals? Not really, as Japanese doesn't pluralize ("5 apple" implies 5 apples, so why bother putting an "s" on the end?) but again, I like to have the specificity. Do languages need to have male or female words? No, because English does not, yet plenty of other languages specify la/le/un/une and so forth.

Specificity is a nice thing to have, I think, and so I'd rather say mascara is on the eyelashes but eyebrows are above the eyelashes, and I wear a coat over my clothes but seawater got on my clothes while washing over it, but I don't need to.

Solution 3:

"Which English words, if any, contain the preposition, on, coupled with a concrete noun to form one word..."

Online springs to mind. There are others, eg onboard. They might begin as separate words but become one word through common usage. Onboard = going on board of the ship. This is common as long as it doesn't lead to ambiguity.

John was busy on line one. (ie on the phone)
John was busy online.

Similarly words like e-mail tend to lose their hyphens over time and become email.

Solution 4:

We do have the prefix supra in English which is equivalent in meaning.

According to m-w.com

Definition of SUPRA- 1 : super- 2a 2 : transcending See supra- defined for kids » Origin of SUPRA- Latin, from supra above, beyond, earlier; akin to Latin super over — more at over