earphones vs headset

earphones

noun
  • A pair of small loudspeakers worn inside each outer ear or covering all or part of the ear, without a connecting band worn over head. 

headset

noun
  • A pair of headphones or earphones, or a singular headphone or earphone, typically with an attached microphone. 

  • On a bicycle, the system of bearings that connects the fork to the frame. 

  • Any electronic device worn on the head. 

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