TROUGH

A 'trough' is a long box-like drinking vessel for farm animals. In other fields, "trough" refers to any kind of (usually elongated) depression:

★ In physics, a trough is the lowest point on a wave.

★ In meteorology, a trough is an elongated region of low atmospheric pressure.

★ In geology, a trough is a long depression less steep than a trench.

★ In statistics and economics, a trough is a noticeable and statistically recordable decline in an economy or graph.

★ In chemistry, a Langmuir-Blodgett trough is a laboratory instrument.
See also trow.