The Collaborative International Dictionary
aestuary
Estuary \Es"tu*a*ry\, n.; pl. Estuaries. [L. aestuarium, from aestuare to surge. See Estuate.] [Written also [ae]stuary.]
A place where water boils up; a spring that wells forth. [Obs.]
--Boyle.-
A passage, as the mouth of a river or lake, where the tide meets the current; an arm of the sea; a frith.
it to the sea was often by long and wide estuaries.
--Dana.