Downcomer
Pronunciation : Down"com`er, n. A pipe to conduct something downwards; specif.: (a) (Iron Manuf.) A pipe for leading the hot gases from the top of a blast furnace downward to the regenerators, boilers, etc. (b) (Steam Engin.) In some water-tube boilers, a tube larger in
Part of Speech : thus
Definition :
completing the circulation.
Source : Webster's Unabridged Dictionary, 1913