bioscope vs feature film

bioscope

noun
  • An early form of movie projector 

feature film

noun
  • The main, full-length film in a cinema program that also included a short film and often a newsreel. As of now, it plays after the trailers. 

  • Any film produced to be shown in cinemas before being released for home viewing. 

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