The term 'roadie gear' refers to the equipment used by a roadie, which is someone who works in the music industry and is responsible for setting up and maintaining musical equipment. The crossword solution for 'amps' is four letters long and refers to amplifiers, which are devices used to increase the volume of sound produced by an instrument or microphone. Amps are an essential part of roadie gear, as they are necessary for amplifying sound during live performances.