What is described as a vertical passageway that conducts flue gases to the atmosphere?

The term that describes a vertical passageway specifically designed to conduct flue gases from a heating appliance to the outside atmosphere is "Chimney or Vent." This terminology encompasses both the structure of the chimney and the functional role it plays in safely directing exhaust gases away from the home, thereby preventing them from re-entering the living space and ensuring that harmful byproducts of combustion are expelled effectively.

In chimney terminology, "flue" refers to the inner lining or passage within the chimney that carries the flue gases. While it is an important component of the chimney system, it does not describe the entire structure. The terms "cricket" and "corbel" refer to different aspects of chimney design and construction; a cricket is a sloped surface used to divert water away from the chimney and a corbel is a structural projection that supports the chimney.