An Etymological Dictionary of Astronomy and Astrophysics

1. A danger that one can foresee but cannot avoid.
   

2. Something causing unavoidable danger, peril, risk, or difficulty.
   

3. The absence or lack of predictability; chance; uncertainty (Dictionary.com).

Etymology (EN): M.E. hasard, from O.Fr. hasard, hasart “game of chance played with dice,” possibly from Sp. azar “an unfortunate card or throw at dice,” postulated to derive from Ar. az-zahr “the die,” but this etymology is controversial.

Etymology (PE): Âpé, from Av. au-pat-, “to fall down, off,” from pat- “to fall, fly;” Proto-Ir. *pat- “to fall; fly; rise;” related to Pers. oftâdan “to fall; to befall; to happen,” → fall. Pers. âfat “blight, pest, curse,” may belong to this family.