Volume Control is a term used to describe the ability to adjust the sound level of an audio device. The three solutions for this term are KNOB (4 letters), FADER (5 letters), and SHH (3 letters). A KNOB is a circular device used to adjust the volume of an audio device. A fader is a sliding control used to adjust the volume of an audio device. SHH is an onomatopoeic term used to indicate a decrease in volume.