TROUGH

(1) A long, narrow, generally shallow receptacle for holding water or feed for animals; any of various similar containers for domestic or industrial use. (2) A gutter under the eaves of a roof. (3) A long, narrow depression, as between waves or ridges. (4) A long but shallow depression in the bed of the sea. (5) (Meteorology) An elongated region of relatively low atmospheric pressure, often associated with a front.