AM 
/ˈeɪˌɛm/ noun
/ˈeɪˌɛm/ noun [noncount] : a system for sending radio signals in which the height of a radio wave is changed in order to send information in the form of sound ◊AM is an abbreviation for amplitude modulation. — compare fm
— AM adjective
▪ listening to my favorite AM station [=a radio station that sends sound using AM] ▪ Is this station AM or FM? ▪ AM radios
▪ listening to my favorite AM station [=a radio station that sends sound using AM] ▪ Is this station AM or FM? ▪ AM radios
