The Collaborative International Dictionary of English v.0.48:

Adustion \A*dus"tion\ (?; 106), n. [L. adustio, fr. adurere,
   adustum: cf. F. adustion.]
   1. The act of burning, or heating to dryness; the state of
      being thus heated or dried. [Obs.] --Harvey.
      [1913 Webster]

   2. (Surg.) Cauterization. --Buchanan.
      [1913 Webster]