The term 'Aqualung Inventor' refers to three people: Cousteau (8 letters), LECHER (6 letters), and Jacques Cousteau (15 letters). Cousteau was a French naval officer, ocean explorer, and inventor who developed the first successful open-circuit scuba diving system, also known as the Aqualung. LECHER was a French engineer who worked with Cousteau to develop the Aqualung. Jacques Cousteau was the son of Cousteau and a renowned oceanographer, filmmaker, and environmentalist who continued his father's work in ocean exploration and conservation.