mouth of a river or strait

A low triangular area where a river divides before entering a larger body of water.
D-shaped area of alluvium at river-mouth.
Tract of land at a river’s mouth, composed of silt deposited as the water slows on entering the sea. Familiar examples of large deltas are those of the Mississippi, Ganges and Brahmaputra, Rhône, Po, Danube, and Nile; the shape of the Nile delta is like the Greek letter delta D, and thus gave rise to the name.
The arcuate delta of the Nile is only one form. Others are birdfoot deltas, like that of the Mississippi which is a seaward extension of the river’s levee system; and tidal deltas, like that of the Mekong, in which most of the material is swept to one side by sea currents. + prikaži više

(French) opening of passage; opening of a passage or tunnel.

ETYM Scot. Related to Frith.
A narrow estuary (especially in Scotland).

ETYM Old Eng. mouth, muth, as. műth.
1. An opening that resembles a mouth (as of a cave or a gorge).
2. The opening of a jar or bottle.
3. A person conceived as a consumer of food.
4. The point where a stream issues into a larger body of water.