The Collaborative International Dictionary of English v.0.48:

Sumption \Sump"tion\, n. [L. sumptio, fr. sumere, sumptum, to
   take.]
   1. A taking. [Obs.] --Jer. Taylor.
      [1913 Webster]

   2. (Logic) The major premise of a syllogism.
      [1913 Webster]