earphones vs headgear

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. 

headgear

noun
  • Anything worn on the head, such as a hat, hood, helmet, etc. 

  • A type of orthodontic appliance attached to dental braces that aids in correcting severe bite problems. 

  • The harness that fits on a horse's head. 

  • The lifting gear at the head of a mine or deep well. 

  • The rigging on the foresail. 

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