The Collaborative International Dictionary of English v.0.48:

Ejector \E*ject"or\, n.
   1. One who, or that which, ejects or dispossesses.
      [1913 Webster]

   2. (Mech.) A jet jump for lifting water or withdrawing air
      from a space.
      [1913 Webster]

   3. That part of the mechanism of a breech-loading firearm
      which ejects the empty shell.
      [Webster 1913 Suppl.]

   Ejector condenser (Steam Engine), a condenser in which the
      vacuum is maintained by a jet pump.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ejector
    n 1: a person who ousts or supplants someone else [syn:
         ouster, ejector]
    2: a mechanism in a firearm that ejects the empty shell case
       after firing [syn: cartridge ejector, ejector]