memory hole

Short definition from Wiktionary

Noun

1. 1
   A figurative place to which information is deliberately sent to be forgotten, or to which forgotten or lost information ends up; nowhere, oblivion.
2. 2
   A fragment of physical address space which does not map to main memory.
3. 3
   Synonym of memory leak (“any of several faults in the memory allocation logic of a computer or program whereby parts of memory become hidden or unusable”).
4. 4
   Alternative form of memory hole.

Verb

1. 1
   To cause something or someone to be forgotten.