Was is the difference between "uparujjhati" & "nirujjhati"? In the Pali, nirujjhati (ni + rudh + ya) appears to be a verb for the noun &quot;nirodha&quot;.

nirujjhati
ceases; dissolves; vanishes.
to be broken up, to be dissolved, to be destroyed, to cease, die

Uparujjhati (upa + rudh + ya) appears similar in etymology, however differs in the prefix.

uparujjhati
stops or ceases
to be stopped, broken, annihilated, destroyed

I have done some examination of the usage of these words in the Pali suttas and, for now, I think their meanings or usages are contextually different.
How can these two words be linguistically distinguished?
They are not synonyms, they have different meanings derived from the same root and different prefixes.

Nirodha means stop, suppress, not allow to go on.
Uparodham means enclose, blockade. 

So aparisesa nirujjhanti means "completely stopped". 

But asesam uparujjhati means "fully enclosed".

So in DN11 the guy was asking about place where the physical processes are completely stopped (aparisesā nirujjhanti).

But Buddha said, that's not what we are talking about. It's about "place" where the physical elements have no footing, place inside which all concepts like beautiful, ugly etc., all namarupas, all conceptual discriminations are fully enclosed or fully en-scoped (asesaṃ uparujjhatī).

It is the universal space of information, the universal space of mind, is where they are all enclosed of course. When all discrimination is stopped and this "space" is seen in its original undivided way, is when the unborn/deathless is attained. It is this space is what we in Mahayana call Shunyata.