A trough is a long, narrow container that holds food or water for animals. On a farm, you might see pigs eating from a trough filled with corn and grain, or horses drinking from a water trough in the pasture. The shape makes it easy for multiple animals to eat or drink at the same time, all lined up along one side.

The word also describes any long, low area or hollow. In geography, an ocean trough is a deep, elongated depression in the seafloor. When you look at ocean waves, the trough is the low point between two wave crests. Scientists studying weather talk about atmospheric troughs, which are zones of low air pressure that can bring stormy conditions.

You might hear people use “trough” figuratively too. If a business experiences a trough in sales, it means their sales have dipped to a low point before (hopefully) rising again. The phrase “feeding at the trough” describes people greedily taking more than their fair share of something, comparing them to pushy farm animals crowding around at dinnertime.