trough

A trough is a long, shallow container or depression used to hold or channel liquids, feed, or other materials, and it also refers to several related features in geology and physics. In everyday use, the most familiar troughs are water troughs and feeding troughs for livestock, usually made of metal, plastic, concrete, or wood. They are designed to be easy to fill and clean, with smooth internal surfaces to minimize contamination, and may include features such as overflow outlets, wide mouths, or sloped bottoms to improve drainage.

In agriculture and animal husbandry, troughs are used to deliver water or feed and can be gravity-fed from a reservoir, plumbed directly to a water supply, or equipped with pumps. Proper sanitation, regular cleaning, and appropriate materials are important to prevent algae growth, bacterial buildup, and injury to animals.

Geologically, a trough is a long, narrow depression or basin in the earth's crust, often formed by subsidence between faults or by slow bending of rock layers. Such troughs can serve as basins for sediments and may influence the location of basinal deposits.

In wave theory, a trough is the low point between two successive crests of a traveling wave. The trough, like the crest, is a point of the wave’s oscillation, and the distance between consecutive troughs equals the wavelength. The term is used across physics, oceanography, and related fields.