Yon

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Old English geon, of Germanic origin; related to German jener ‘that one’.

wiktionary

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From Middle English yon, from Old English ġeon, from Proto-Germanic *jainaz.

yon

etymonline

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yon (adj., pron.)

Old English geon "that (over there)," from Proto-Germanic *jaino- (source also of Old Frisian jen, Old Norse enn, Old High German ener, Middle Dutch ghens, German jener, Gothic jains "that, you"), from PIE pronominal stem *i- (source also of Sanskrit ena-, third person pronoun, anena "that;" Latin idem "the same," id "it, that one;" Old Church Slavonic onu "he;" Lithuanian ans "he"). As an adverb from late 15c., a shortening of yonder.