The Collaborative International Dictionary of English v.0.48:

Condenser \Con*dens"er\, n.
   1. One who, or that which, condenses.
      [1913 Webster]

   2. (Physic)
      (a) An instrument for condensing air or other elastic
          fluids, consisting of a cylinder having a movable
          piston to force the air into a receiver, and a valve
          to prevent its escape.
      (b) An instrument for concentrating electricity by the
          effect of induction between conducting plates
          separated by a nonconducting plate.
      (c) A lens or mirror, usually of short focal distance,
          used to concentrate light upon an object.
          [1913 Webster]

   3. (Chem.) An apparatus for receiving and condensing the
      volatile products of distillation to a liquid or solid
      form, by cooling.
      [1913 Webster]

   4. (Steam Engine) An apparatus, separate from the cylinder,
      in which the exhaust steam is condensed by the action of
      cold water or air. See Illust. of Steam engine.
      [1913 Webster]

   Achromatic condenser (Optics), an achromatic lens used as a
      condenser.

   Bull's-eye condenser, or Bull's-eye (Optics), a lens of
      short focal distance used for concentrating rays of light.


   Injection condenser, a vessel in which steam is condensed
      by the direct contact of water.

   Surface condenser, an apparatus for condensing steam,
      especially the exhaust of a steam engine, by bringing it
      into contact with metallic surface cooled by water or air.
      [1913 Webster]

WordNet (r) 3.0 (2006):

condenser
    n 1: an electrical device characterized by its capacity to store
         an electric charge [syn: capacitor, capacitance,
         condenser, electrical condenser]
    2: an apparatus that converts vapor into liquid
    3: a hollow coil that condenses by abstracting heat
    4: lens used to concentrate light on an object [syn:
       condenser, optical condenser]