The Collaborative International Dictionary of English v.0.48:

Prosthesis \Pros"the*sis\, n. [L., fr. Gr. ? an addition, fr. ?
   to put to, to add; ? to + ? to put, place.]
   1. (Surg.) The addition to the human body of some artificial
      part, to replace one that is wanting, as a log or an eye;
      -- called also prothesis.
      [1913 Webster]

   2. (Gram.) The prefixing of one or more letters to the
      beginning of a word, as in beloved.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prothesis \Proth"e*sis\, n. [NL., fr. Gr. ? a placing in public,
   fr. ? to set before; ? before + ? to set, put.]
   1. (Eccl.) A credence table; -- so called by the Eastern or
      Greek Church.
      [1913 Webster]

   2. (Med.) See Prosthesis. --Dunglison.
      [1913 Webster]