Ventilation tube, also known as a DUCT, is a tube-like structure used to provide ventilation in buildings. It is typically made of metal or plastic and is used to transport air from one area to another. The term 'DUCT' is derived from the Latin word for 'PIPE' and is used to describe any type of enclosed conduit that carries air. Ventilation tubes are commonly used in heating, ventilation, and air conditioning systems.