estuary

n. place where the river current meets the sea tide (as in the mouth of a river)

For other meanings, see Estuary (disambiguation) An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries are often associated with high rates of biological productivity. An estuary is where the river meets the sea.An estuary is typically the tidal mouth of a river (aestus is Latin for tide), and estuaries are often characterized by sedimentation or silt carried in from terrestrial runoff and, frequently, from offshore. They are made up of brackish water. Estuaries are more likely to occur on submerged coasts, where the sea level has risen in relation to the land; this process floods valleys to form rias and fjords. These can become estuaries if there is a stream or river flowing into them. Large estuaries, like Chesapeake Bay and Puget Sound often have many streams flowing into them and can have complex shapes. Estuaries are often given names like bay, sound, fjord, etc. The terms are not mutually exclusive. Where an enormous volume of river water enters the sea (as, for example, from the Amazon into the South Atlantic) its estuary could be considered to extend well beyond the coast.
See more at Wikipedia.org...

Noun
1. the wide part of a river where it nears the sea; fresh and salt water mix
(hypernym) body of water, water
(hyponym) firth
(part-holonym) river

(n.)
A place where water boils up; a spring that wells forth.
  

(n.)
A passage, as the mouth of a river or lake, where the tide meets the current; an arm of the sea; a frith.
  

(a.)
Belonging to, or formed in, an estuary; as, estuary strata.
  

The lower end of a river, or a semi-enclosed coastal body of water with access to the open ocean, which is affected by the tides and where fresh and salt water mix. (DOI3)