- 1[countable] a long, narrow, open container for animals to eat or drink from
- 2the trough [singular] (informal) if you say that people have their noses in the trough, you mean that they are trying to get a lot of money for themselves
- 3[countable] (technology) a long, narrow region of low air pressure between two regions of higher pressure compare ridge
- 4[countable] a period of time when the level of something is low, especially a time when a business or the economy is not growing There have been peaks and troughs in the long-term trend of unemployment.
- 5[countable] a low area between two waves in the ocean, or two hills