a long shallow receptacle for the food or drinking water of domestic animals
any of various similar containers used for domestic or industrial purposes
a drain or channel for water; esp a gutter along the eaves of a building
a long narrow or shallow trench, e.g. between waves or ridges
a long shallow depression in the bed of the sea
in meteorology, an elongated area of low atmospheric pressure: compare ridge1
in physics, a minimum point in a wave or an alternating signal
any notably low point in activity or achievement, e.g. in a trade cycle or on a statistical graph
[Old English trog]