Part of speech: Adjective (satellite)
distant but within sight (`yon' is dialectal)
Example: yonder valley; the hills yonder; what is yon place?
Part of speech: Adverb
at or in an indicated (usually distant) place (`yon' is archaic and dialectal)
Example: the house yonder; scattered here and yon"- Calder Willingham
The word "yon". It started in Proto-Germanic *jainaz, which. Then it appeared in Old English ġeon, which. Later, people used it in Middle English yon.
This word traces back to ancient languages spoken thousands of years ago, long before English even existed!