The Collaborative International Dictionary of English v.0.48:

Tentation \Ten*ta"tion\, n. [L. tentatio: cf. F. tentation. See
   Temptation.]
   1. Trial; temptation. [Obs.] --Sir T. Browne.
      [1913 Webster]

   2. (Mech.) A mode of adjusting or operating by repeated
      trials or experiments. --Knight.
      [1913 Webster]