General terms:
* River mouth: This refers to the point where a river empties into a larger body of water like a lake, sea, or ocean.
* River delta: This is a landform created at the mouth of a river where it deposits sediment, forming a fan-shaped area.
* Estuary: This is a partially enclosed body of water where freshwater from a river mixes with saltwater from the sea.
* Creek: This is a small stream or river, often used for a smaller inlet into a larger river.
More specific terms:
* Arm: This can refer to a branch of a river, often a smaller tributary that flows into the main river.
* Channel: This refers to the main flow path of a river, especially when referring to a specific part of the river that is narrower than others.
* Bayou: This is a slow-moving, swampy waterway, often found in Louisiana.
* Slough: This is a stagnant or slow-moving body of water, often with a muddy bottom, that might connect to a river.
To help you choose the best synonym, consider:
* The size and shape of the inlet: Is it a narrow channel, a wide delta, or something in between?
* The type of water: Is it freshwater, saltwater, or a mix?
* The context: What is the inlet used for? Navigation, fishing, recreation?
Let me know if you can provide more context about the river inlet you are referring to, and I can give you a more specific synonym.