[trawf, trof or, sometimes, trawth, troth] 
| 1. | a long, narrow, open receptacle, usually boxlike in shape, used chiefly to hold water or food for animals. |
| 2. | any of several similarly shaped receptacles used for various commercial or household purposes. |
| 3. | a channel or conduit for conveying water, as a gutter under the eaves of a building for carrying away rain water. |
| 4. | any long depression or hollow, as between two ridges or waves. |
| 5. | Oceanography. a long, wide, and deep depression in the ocean floor having gently sloping sides, wider and shallower than a trench. Compare trench (def. 4). |
| 6. | Meteorology. an elongated area of relatively low pressure. |
| 7. | the lowest point, esp. in an economic cycle. |
| trough (trôf, trŏf) n.
[Middle English, from Old English trog; see deru- in Indo-European roots.] |
Trough
The stage of the economy's business cycle that marks the end of a period of declining business activity and the transition to expansion. 
Investopedia Commentary
In general, the business cycle is said to go through expansion, then the peak, followed by contraction, and then it finally bottoms out with the trough.
Related Links
Recession: What Does It Mean To Investors?
The Ups And Downs Of Investing In Cyclical Stocks
The Stages Of Industry Growth
Peak-and-Trough Analysis
See also: Bottom, Business Cycle, Contraction, Expansion, Peak, Recession