garbage collector

noun2

1. •
   (US, Canada) A worker who removes refuse, especially from properties.

   • the mayor of Maycomb asked us to please help the garbage collector by dumping our own trees and trash. — 1960
2. •
   An algorithm, procedure or thread dedicated to garbage collection: reclaiming resources which are no longer in use.

   • Java uses a technique known as garbage collection to remove objects that are no longer needed. The garbage collector is Java's grim reaper. — 2002