a pipe, tube, or passage for conducting fluid materials downward.
Origin of downcomer
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for downcomer
But I dreaded to be found eating, alone in that vast room, by the first downcomer.Seven Men|Max Beerbohm
a pipe that connects a cistern to a WC, wash basin, etcAlso called: downcome
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012