A Sound is often formed by the sea flooding a river valley.

Sometimes a Sound is made by a glacier carving out a valley on the coast then melting back, or the sea moving into a glacier valley.

Puget Sound, off the northwest coast, is an arm of the Pacific Ocean. It is a boater's paradise.

Related Terms
coast - a sound has a lot of coastline
glacier - often creates an area that becomes a sound
island - there can be many islands on a sound
ocean - connected to a sound

there are many coves, bays, peninsulas, straits, channels, river mouths and estuaries, harbors and lagoons on a sound