Trough

TROUGH, noun trauf.

1. A vessel hollow longitudinally, or a large log or piece of timber excavated longitudinally on the upper side; used for various purposes.

2. A tray. [This is the same word dialectically altered.]

3. A canoe; the rude boat of uncivilized men.

4. The channel that conveys water, as in mills.

The trough of the sea, the hollow between waves.