The term 'Sound of a Sneeze' can be represented by two different crossword solutions: AHCHOO (6 letters) and ACHOO (5 letters). A sneeze is an involuntary reflex action that is caused by irritation in the nose, usually due to a cold or allergies. It is characterized by a sudden, loud exhalation of air through the nose and mouth. The sound of a sneeze is often represented by the words 'ahchoo' or 'achoo'.