I don't have references for this, but I would be inclined to refer to your unnamed elements as superstrings, because your question is not really about prefixes, but about (prefixed) substrings; and a string that contains substrings can easily and logically be referred to as a superstring. (If you want to be more specific about it, you could call them "containing superstrings", which seems more appropriate in your example 2.)
Answer from Hellion on Stack ExchangeI don't have references for this, but I would be inclined to refer to your unnamed elements as superstrings, because your question is not really about prefixes, but about (prefixed) substrings; and a string that contains substrings can easily and logically be referred to as a superstring. (If you want to be more specific about it, you could call them "containing superstrings", which seems more appropriate in your example 2.)
You would probably do well to use the word elongation.
ban is a prefix substring of banana so banana is an elongation of ban.
The word extension came to mind first, but in computer science, extension refers frequently to a filetype extension following a dot, so that could be confusing when used in a separate context. Elongation carries the same meaning without the risk of confusing readers or listeners.
Per Merriam-Webster definition 2:
a : the state of being elongated or lengthened; also : the process of elongating
b : something that is elongated
I'm trying to figure out the literal opposite of the word 'subsequent'. Would it be 'prosequent'?
To expand on this a bit, there are many of these prefixes which have seemly identical uses. Are there slight variations in their meaning? Why are there so many? Is the abundance of such prefixes related to the English language's diverse origins?
So the ways of using "in-" I'm curious about would be for words such as "in-definite" or "in-determinate".
Now I know the opposite of those words would be definite and determinate respectively, but just honing in on the "in-" part for those uses, what would be the explicit opposite prefix? I don't think it's "ex-" or "en-"...
Any input will be greatly appreciated :)