nth vs unspecified

nth

noun

  • The item at position n in a sequence. 

  • The item in a relatively large but unspecified position in a series. 

adj

  • Occurring at a relatively large but unspecified position in a series. 

  • Occurring at position n in a sequence. 

unspecified

adj

  • Not specified; not thoroughly explained or detailed; not adequately commented. 

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