am·pli·fi·er 
/ˈæmpləˌfajɚ/ noun
plural am·pli·fi·ers /ˈæmpləˌfajɚ/ noun [count] : a device that increases the strength of electric signals so that sounds played through an electronic system are louder
▪ He plugged his electric guitar into an amplifier. —called also (informal) amp
▪ He plugged his electric guitar into an amplifier. —called also (informal) amp
