trough

Concise Oxford English Dictionary © 2008 Oxford University Press:
trough/trɒf/

▶noun

• 1 a long, narrow open container for animals to eat or drink out of.

  ■ a similar container, e.g. one for growing plants.

• 2 a channel used to convey a liquid.

  ■ a long hollow in the earth's surface.

• 3 an elongated region of low barometric pressure.

• 4 a hollow between two wave crests in the sea.

• 5 a region around the minimum on a curve of variation of a quantity.

  ■ a point of low activity or achievement.

▶verb informal eat greedily.

– origin OE trog, of Gmc origin; rel. to tree.