trough

1 a long hollow cylinder for carrying a substance (as a liquid or gas) <all of the wiring for the converted residential loft is concealed in a vertical trough> Synonyms channel, conduit, duct, leader, line, penstock, pipe, tubeRelated Words drain, drainpipe, funnel, hydrant, main, smokestack, spout, standpipe, stovepipe, tile, waste pipe, waterspout; pipage (or pipeage), pipeline, piping

2 a long narrow channel dug in the earth <I slid and fell into the trough by the side of the road, scraping my leg> Synonyms dike, fosse (or foss), gutter, sheugh [chiefly Scottish], trench, ditchRelated Words acequia [Southwest], culvert, drain, draw, gully (also gulley), ravine; drill, furrow; ha-ha, moat, stank [British dialect], sunk fence; kennel

3 a pipe or channel for carrying off water from a roof <the troughs on the eaves of the house were clogged with leaves> Synonyms drainpipe, eaves trough, rainspout, spout, gutter, waterspoutRelated Words drain, flume, sluice; conduit, duct; aqueduct