chimney
A freestanding vertical conduit for the passage and emission of smoke, steam, or other gas.
Pictured: Schoorsteen Jannink
A chimney (as an individual structure) is a freestanding smokestack, vent, flue pipe, or other emissions tower. If it is attached to another type of structure then it is not considered freestanding, and it belongs to that other structure as a building feature. A freestanding chimney may rise out of a subsidiary podium structure which serves no major role other than to direct emissions into the chimney.
The conduit carries emissions upward as an independent structure. A subsidiary podium used mainly to direct those emissions can form its base.
A chimney attached to a different building remains a feature of that building. Its height alone does not make an attached chimney freestanding.
