|part of speech:
||a long narrow open container used for serving food or water to animals.
The pigs gathered at the trough.
||any long narrow depression or channel, such as a gutter, a narrow valley, or the depression in water between two waves.
||in meteorology, a long narrow region of low barometric pressure relative to the surrounding area.
||a low point on a graph, esp. a low point of a cyclic function.
||channel, groove, gully, launder, tube