ejector ejector /ɪˈʤɛktər/

noun

1. A mechanism in a firearm that ejects the empty shell case after firing  ( cartridge ejector , ejector )
   a mechanism in a firearm that ejects the empty shell case after firing
   
2. A person who ousts or supplants someone else  ( ejector , ouster )
   a person who ousts or supplants someone else