I understand that nonetymological / unetymological mean "not etymological" – i.e. something which doesn’t have any roots in formation. But I am unable to grasp its significance – does it mean "absolute" words which can’t be broken down, and hence have no etymology? Or words that don’t have any roots (how can something not have any roots?)
I couldn’t understand the intent of using this word in this sentence:
A siphon (from Ancient Greek: σίφων, "pipe, tube", also spelled nonetymologically syphon)…
also spelled nonetymologically syphon [my emphasis]
That is, there is no etymological justification for replacing the ‹i›, representing Greek iota, with a ‹y›, which ordinarily represents Greek upsilon. The ‹y› reflects English pronunciation of the word rather than its Greek origin.