headphone       
adjective [ before noun ] uk/ˈhed.fəʊn/ us/ˈhed.foʊn/
 耳机的
for or relating to headphones
  The speaker set plugs into any standard headphone jack. 这套扬声器可以插入任何标准的耳机插孔。 
 He twirled the headphone cord through his long fingers. 他用长长的手指捻转动着耳机线。 
 - More examples
 - Even headphone sockets are included for rear passengers.
 - There may be debris in the headphone port.
 - Some systems are intended for headphone listening.