The term 'FLUTE's Cousin' refers to three musical instruments that are related to the FLUTE. The first is the PICCOLO, which is a small FLUTE with a higher pitch than a regular FLUTE. The second is the RECORDER, which is a wooden FLUTE-like instrument that has been used since the Middle Ages. The third is the GOBLET, which is a type of FLUTE with a conical bore and a cup-shaped mouthpiece. All three instruments are related to the FLUTE and are commonly referred to as 'FLUTE's Cousins'.