An inlet is an indentation of a shoreline, usually long and narrow, such as a small bay or arm, that often leads to an enclosed body of water, such as a sound, bay, lagoon, or marsh. In sea coasts, an inlet usually refers to the actual connection between a bay and the ocean and is often called an "entrance" or a recession in the shore of a sea, lake, or river. A certain kind of inlet created by glaciation is a fjord, typically but not always in mountainous coastlines and also in montane lakes.
Complexes of large inlets or fjords may be called sounds, e.g., Puget Sound, Howe Sound, Karmsund (sund is Scandinavian for "sound"). Some fjord-type inlets are called canals, e.g., Portland Canal, Lynn Canal, Hood Canal, and some are channels, e.g., Dean Channel and Douglas Channel.(Wikipedia)