The Collaborative International Dictionary of English v.0.48:

Autoclave \Au"to*clave\, n. [F., fr. Gr. a'yto`s self + L.
   clavis key.]
   1. A kind of French stewpan with a steam-tight lid. --Knight.
      [1913 Webster]

   2. a device used for sterilizing objects by exposing them to
      steam at above atmospheric pressure (and thus at a
      temperature above the normal boiling point of water). It
      consists of a closed chamber able to withstand internal
      pressure, and a means of passing superheated steam into
      the chamber. Autoclaves are made in various sizes, and are
      much used in hospitals and research laboratories to render
      instruments and equipment sterile.
      [PJC]

WordNet (r) 3.0 (2006):

autoclave
    n 1: a device for heating substances above their boiling point;
         used to manufacture chemicals or to sterilize surgical
         instruments [syn: autoclave, sterilizer, steriliser]
    v 1: subject to the action of an autoclave