Fenland and Swale

Fenland noun - Low-lying wet land with grassy vegetation; usually is a transition zone between land and water.

Swale and fenland are semantically related. In some cases you can use "Swale" instead a noun "Fenland".

Swale noun - A low area (especially a marshy area between ridges).

Fenland and swale are semantically related. Sometimes you can use "Fenland" instead a noun "Swale".