noun (n)

• 100 fen equal 1 yuan in China(noun.quantity)

  source: wordnet30
• low-lying wet land with grassy vegetation; usually is a transition zone between land and water(noun.object)

  Example:
  The fens of eastern England.
  

  Synonym:
  fenland, marsh, marshland
  

  source: wordnet30
• Low land overflowed, or covered wholly or partially with water, but producing sedge, coarse grasses, or other aquatic plants; boggy land; moor; marsh.(noun)

  source: webster1913