Air leak sound is a term used to describe the sound of air escaping from a hole or crack. The most common sound associated with an air leak is a HISS, which is represented by the 4 letter word 'HISS'. Another sound associated with an air leak is a SSS, which is represented by the 3 letter word 'SSS'. A more intense sound associated with an air leak is ssss, which is represented by the 4 letter word 'SSSS'.