The term HI-FI PART is composed of three components: AMP (3 letters), STEREO (6 letters). An AMP, or amplifier, is an electronic device that increases the power of a signal. It is used to increase the volume of audio signals, such as music, and is an essential part of any hi-fi system. A STEREO is a type of sound system that uses two or more channels to create a more realistic sound experience. It is also an important component of a hi-fi system. Together, these two components form the basis of a hi-fi system, allowing for a higher quality of sound reproduction.