http://forum.wordreference.com/showthread.php?t=9252The NEW OXFORD Dictionary
OF ENGLISH
yon poetic/literary or dialect
determiner & adverb yonder; that: [as DETERMINER] there's some big ranches yon side of the Sierra.
pronoun yonder person or thing: what do you make of yon?
PHRASES
hither and yon another term for HITHER AND THITHER.
ORIGIN Old English geon, of Germanic origin; related to German jener ‘that one’.
Definition
yonder [Show phonetics]
determiner, adverb (ALSO yon) OLD USE
in the place or direction shown; over there
Silent night, holy night!
All is calm, all is bright
'Round yon virgin mother and child.
...meaning that all is calm and all is bright around that virgin over there--the mother and her baby (mother and child forming a plural appositive for virgin).