Fen \Fen\, n. [AS. fen, fenn, marsh, mud, dirt; akin to D. veen, OFries. fenne, fene, OHG. fenna, G. fenn, Icel. fen, Goth. fani mud.]

Low land overflowed, or covered wholly or partially with water, but producing sedge, coarse grasses, or other aquatic plants; boggy land; moor; marsh.

'Mid reedy fens wide spread. --Wordsworth.

Note: Fen is used adjectively with the sense of belonging to, or of the nature of, a fen or fens.

Fen boat, a boat of light draught used in marshes.

Fen duck (Zo["o]l.), a wild duck inhabiting fens; the shoveler. [Prov. Eng.]

Fen fowl (Zo["o]l.), any water fowl that frequent fens.

Fen goose (Zo["o]l.), the graylag goose of Europe. [Prov. Eng.]

Fen land, swamp land.

Source: Webster's Revised Unabridged Dictionary (1913)