A hiss canal or duct refers to a passageway found in some reptiles, particularly snakes, which allows them to produce their characteristic hissing sound. Synonyms for hiss canal or duct include "vent", which is a term commonly used in the scientific community. Another alternative is "exhalatory duct", which emphasizes the function of expelling air for producing the hissing sound. Additionally, some might refer to this structure as a "hissing pathway", highlighting its role in enabling the reptile's unique vocalization. Regardless of the term used, the hiss canal or duct plays a crucial role in the communication and defense mechanisms of snakes and other reptiles.