barachois
A coastal lagoon partially or totally separated from the ocean by a sand or shingle bar.
These barachois are inland lagoons connected with the main lagoon by a narrow outlet some 2 fathoms deep or more. They are filled and emptied every tide, and their floor is intersected by numerous small channels running in every direction[…]
Where it comes from
From French barachois, from Basque barratxoa (“little bar”).
Adapted from the Wiktionary entry barachois (CC BY-SA 4.0).