The term 'Drum Companion' is a job description for someone who plays the fife, which is a small, high-pitched flute-like instrument. The fife is often used in military and marching bands, as well as in traditional folk music. The term 'fife' is derived from the German word 'pfeife', which means pipe. The drum companion is responsible for providing a rhythmic accompaniment to the drums, creating a more dynamic sound.