Fen (noun)

1. A low-lying area of marshy ground, typically fed by ground water or by water from nearby rivers or lakes.
2. A wetland area that is dominated by grasses, sedges, reeds, and other herbaceous plants.

Origin:

Old english fenn, of germanic origin; related to dutch ven and german fenn, from an indo-european root shared by greek peiros "marsh".

Examples:

1. The fen was home to many species of birds.
2. The fen was drained to make way for farmland.
3. The fen is a unique and fragile ecosystem.
4. The fen is a valuable resource for peat, reeds and other materials.
5. The fen provides important habitat for many aquatic species.