What is Bon?

Legal Definition
Bon or Bön (Tibetan: བོན་, Wylie: bon, Lhasa dialect IPA: [pʰø̃̀]) is a Tibetan religion, which self-identifies as being distinct from Tibetan Buddhism, although it shares the same overall teachings and terminology. It arose in the eleventh century and established its scriptures mainly from termas and visions by tertöns such as Loden Nyingpo. Though Bon terma contain myths of Bon existing before the introduction of Buddhism in Tibet, "in truth the 'old religion' was a new religion."
-- Wikipedia
Legal Definition
Fr. In old French law. A royal order or check on the treasury, invented by Francis I. Bon pour mille livres, good for a thousand livres. Step. Lect. 387. In modern law. The name of a clause (bon pour -----, good for so much) added to a cedule or promise, where it is not in the handwriting of the signer, containing the amount of the sum which he obliges himself to pay. Poth. Obi. part 4, ch. 1, art. 2, § 1.
-- Black's Law Dictionary
Legal Definition
Good.
-- Ballentine's Law Dictionary