trough / trôf/ • n. a long, narrow open container for animals to eat or drink out of: a water trough. ∎  a container of a similar shape used for a purpose such as growing plants or mixing chemicals. ∎  a channel used to convey a liquid. ∎  a long hollow in the earth's surface: a vast glacial trough. ∎  an elongated region of low atmospheric pressure. ∎  a hollow between two wave crests in the sea. ∎  a low level of economic activity. ∎  Math. a region around the minimum on a curve of variation of a quantity. ∎  a point of low achievement or satisfaction: learning a language is a series of peaks and troughs.

trough
1. An extension of low atmospheric pressure from the central regions of a low-pressure system into a zone where generally higher pressure prevails. The term ‘trough’ is also, and in accordance with this definition, applied to equatorward meanders of the flow of the upper westerly winds over middle latitudes. (The ‘equatorial trough’, where trade winds meet, is synonymous with the ‘intertropical convergence zone’.) See also LONG WAVE.

2. The lowest point of a fold surface.

trough
1. An extension of low atmospheric pressure from the central regions of a low-pressure system into a zone where generally higher pressure prevails.

2. A meander towards the equator in the flow of the upper westerly winds over middle latitudes. (The ‘equatorial trough’, where trade winds meet, is synonymous with the intertropical convergence zone’.)

trough oblong open vessel, esp. to contain liquid OE.; channel, pipe XIV; hollow, valley XVI; t. of the sea hollow on the surface between waves XVII. OE. trog = OS. trog, OHG. troc (Du., G. trog), ON. trog :- Gmc. *truzaz :- IE. *drukós, f. *dru- wood, TREE.

trough In meteorology, area of low atmospheric pressure, usually an extension to a depression. The opposite are ridges of high pressure.