bookmark vs separator

bookmark

noun
  • A strip of material used to mark a place in a book. 

  • A record of the address of a file or Internet page, serving as a shortcut to it. 

  • A pointer found in a nonclustered index to a row in a clustered index or a table heap 

verb
  • To create a bookmark. 

separator

noun
  • An object located between two or more things and hence separating them. 

  • One who separates; an agent performing the action of separating. 

  • A device for removing one substance from another, such as cream from milk. 

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