estuary
UK: ˈɛstjʊəri | US: ˈɛstʃuˌɛri
n. A partially enclosed coastal body of brackish water where freshwater from rivers and streams meets and mixes with saltwater from the ocean.
n. (Ecology) A transitional ecosystem characterized by tidal flow and high biodiversity.
The word traces back to Latin aestuarium, linked to aestus (tide), which metaphorically evoked both tidal motion and heat (via boiling water). Over time, aestuarium narrowed to describe tidal river mouths in Medieval Latin, later entering English as estuary (16th century). The suffix -ary solidifies its meaning as a geographic feature.
The Thames estuary is a vital habitat for migratory birds.
Sediment deposits in the estuary create fertile mudflats.
Pollution threatens the delicate balance of estuary ecosystems.
The boat sailed into the estuary at high tide.
Mangroves often fringe tropical estuaries, providing coastal protection.