The term 'Leaky Tire Sound' refers to the sound of air escaping from a tire with a puncture. It is usually described as a hissing or whistling sound, and is often accompanied by a decrease in tire pressure. The crossword solutions for this term are SSS (3 letters) and SSSS (4 letters), which stand for 'Ssss' and 'Sssss', respectively. These are onomatopoeic representations of the sound made by a leaky tire.