The Collaborative International Dictionary of English v.0.48:

Ordeal \Or"de*al\ ([^o]r"d[-e]*al), n. [AS. ord[=a]l, ord[=ae]l,
   a judgment; akin to D. oordeel, G. urteil, urtheil; orig.,
   what is dealt out, the prefix or- being akin to [=a]-
   compounded with verbs, G. er-, ur-, Goth. us-, orig. meaning,
   out. See Deal, v. & n., and cf. Arise, Ort.]
   1. An ancient form of test to determine guilt or innocence,
      by appealing to a supernatural decision, -- once common in
      Europe, and still practiced in the East and by savage
      tribes.
      [1913 Webster]

   Note: In England ordeal by fire and ordeal by water were
         used, the former confined to persons of rank, the
         latter to the common people. The ordeal by fire was
         performed, either by handling red-hot iron, or by
         walking barefoot and blindfold over red-hot plowshares,
         laid at unequal distances. If the person escaped
         unhurt, he was adjudged innocent; otherwise he was
         condemned as guilty. The ordeal by water was performed,
         either by plunging the bare arm to the elbow in boiling
         water, an escape from injury being taken as proof of
         innocence, or by casting the accused person, bound hand
         and foot, into a river or pond, when if he floated it
         was an evidence of guilt, but if he sunk he was
         acquitted. It is probable that the proverbial phrase,
         to go through fire and water, denoting severe trial or
         danger, is derived from the ordeal. See Wager of
         battle, under Wager.
         [1913 Webster]

   2. Any severe trial, or test; a painful experience.
      [1913 Webster]

   Ordeal bean. (Bot.) See Calabar bean, under Calabar.

   Ordeal root (Bot.) the root of a species of Strychnos
      growing in West Africa, used, like the ordeal bean, in
      trials for witchcraft.

   Ordeal tree (Bot.), a poisonous tree of Madagascar
      (Tanghinia venenata syn. Cerbera venenata). Persons
      suspected of crime are forced to eat the seeds of the
      plumlike fruit, and criminals are put to death by being
      pricked with a lance dipped in the juice of the seeds.
      [1913 Webster]