Trough

A trough is a box-like drinking vessel for farm animals.  Other senses of the word refer to things that are lower than their surroundings, like a trough:

 Trough (physics)
 Trough (meteorology);
 Trough (geology);
 a trough is also a noticeable and statistically recordable decline in an economy or graph.
 in chemistry it can be a Langmuir Blodgett Trough

See also trow.