The Collaborative International Dictionary of English v.0.48:

anabasis \a*nab"a*sis\ ([.a]*n[a^]b"[.a]*s[i^]s), n. [Gr.
   'ana`basis, fr. 'anabai`nein to go up; 'ana` up + bai`nein to
   go.]
   1. A journey or expedition up from the coast, like that of
      the younger Cyrus into Central Asia, described by Xenophon
      in his work called "The Anabasis."
      [1913 Webster]

            The anabasis of Napoleon.             --De Quincey.
      [1913 Webster]

   2. (Med.) The first period, or increase, of a disease;
      augmentation. [Obs.] AS
      [1913 Webster]

   3. (Med) A plant genus of the goosefoot family
      Chenopodiaceae.
      [AS]