hashtag vs rehash

hashtag

noun
  • The hash sign itself, when used as part of a hashtag. 

  • A metadata tag, signaled by a preceding hash sign (#), used to label content. 

verb
  • To label (a message) with a hashtag. 

rehash

noun
  • A recomputation of the structure of a hash table, taking into account any newly added items. 

  • Something reworked, or made up from old materials. 

verb
  • To repeat with minor variation. 

  • To analyze a prior contentious or embarrassing event. 

  • To hash (chop food into small pieces) again. 

  • To recompute the structure of a hash table, taking into account any newly added items. 

How often have the words hashtag and rehash occurred in a corpus of books? (source: Google Ngram Viewer )