Mass Media

The chart below is a Google Ngram which shows the use of the term "mass media" in all books scanned by Google from 1900 to 2000.
 
The phrase is unknown before the 1940s when it started to be used as a collective term for newspapers, magazines, radio and cinema.  It really took off when television arrived.
 
The use of the word "media" in its modern context only started with the arrival of radio in the 1920. Before that the collective terms for what we now call media were simply "print" or "the press"
 
 
Incidence of term "mass media" in books
 
 
 The Ngram viewer is a fascinating research tool and can be found at: