FM  
noun uk/ˌefˈem/ us/ˌefˈem/
  (RADIO)      
 [ U ]调频 
abbreviation for frequency modulation: a radio system for broadcasting that produces a very clear sound
  You can listen to the BBC World Service 24 hours a day on FM.
 They had an FM radio.
 - More examples
 - When we first got digital radio it sounded so much worse than FM.
 - He enjoys listening to Jazz FM in his car.
 - Popular Spanish-language FM stations include La Mega and Amor.