Definitions of yon:

• adjective:   distant but within sight (`yon' is dialectal)

  Example: "Yonder valley"

• adverb:   at or in an indicated (usually distant) place (`yon' is archaic and dialectal)

  Example: "The house yonder"

• name:  A female given name (rare: 1 in 100000 females; popularity rank in the U.S.: #3189)
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #7863)