Marsh
Part of speech: noun
Definition: An area of low, wet land, often with tall grass.
Example sentence: I do mourn my characters. I wrote an essay once where I was sure that far back in a marsh there was a hummock - a little hill of hardwoods - and an old farm house, where all the heroines in my novels lived together with all my beloved dead dogs. I've discussed this with my therapist, naturally. He says it's okay in fair amounts.
Fenland
Part of speech: noun
Definition: Low-lying ground, often wet or marshy