from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The part of the wide lower course of a river where its current is met by the tides.
  • n. An arm of the sea that extends inland to meet the mouth of a river.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Coastal water body where ocean tides and river water merge.
  • n. An ocean inlet also fed by fresh river water.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Belonging to, or formed in, an estuary.
  • 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.

from The Century Dictionary and Cyclopedia

  • n. An arm or inlet of the sea, particularly one that is covered by water only at high tide.
  • n. That part of the mouth or lower course of a river flowing into the sea which is subject to tides; specifically, an enlargement of a river channel toward its mouth in which the movement of the tides is very prominent.
  • n. A place where water boils up.
  • Belonging to or formed in an estuary: as, estuary strata.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the wide part of a river where it nears the sea; fresh and salt water mix


Latin aestuārium, from aestus, tide, surge, heat.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin aestuarium ("creek”, “estuary of a river"). (Wiktionary)



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