A chimney a structure for venting hot flue gases or smoke from a boiler, stove, furnace or fireplace to the outside atmosphere. Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney, effect. The space inside a chimney is called a flue. Chimneys may be found in buildings, steam locomotives and ships. In the United States, the term smokestack (colloquially, stack) is also used when referring to locomotive chimneys or ship chimneys, and the term funnel can also be used. The height of chimneys plays a role in their ability to transfer flue gases using stack effect, the dispersion of pollutants at higher altitude helps to ease down its influence on surroundings....'
Contributions by Mbeychok, Arpingstone, and Milducks.