Definitions

1. noun

A body of water where the tide comes in and out, forming a partially enclosed coastal body of water, typically with a narrow entrance and a large surface area, such as a bay, gulf, or harbor.

“The estuary is a vital habitat for migratory birds.”

2. noun

A part of a stream or river that flows into a larger body of water.

“The estuary of the river marked the beginning of the ocean.”