Lewis & Short

encăthisma, ătis, n., = ἐγκάθισμα,

  1. I. a sitting bath, Cael. Aur. Acut. 3, 18; id. Tard. 5, 4, 69; Sext. Plac. 9, 17.
  2. II. A fomentation, Cael. Aur. Tard. 2, 1, 23.