The term 'FAN NOISE' can be broken down into five distinct words: HUM (3 letters), YEA (3 letters), RAH (3 letters), BOO (3 letters), and WHIR (4 letters). HUM is a low, continuous sound, often used to express contentment or pleasure. YEA is an expression of agreement or enthusiasm. Rah is an exclamation of encouragement or approval. BOO is an expression of disapproval or contempt. Finally, WHIR is a sound made by a rapidly rotating object. Together, these words describe the various noises that a fan can make.