A fen is one of the main types of wetland, the others being grassy marshes, forested swamps, and peaty bogs. Along with bogs, fens are a kind of mire. Fens are usually fed by mineral-rich surface water or groundwater. They are characterised by their water chemistry, which is pH neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients. They are usually dominated by grasses and sedges, and typically have brown mosses in general including Scorpidium or Drepanocladus. Fens frequently have a high diversity of other plant species including carnivorous plants such as Pinguicula. They may also occur along large lakes and rivers where seasonal changes in water level maintain wet soils with few woody plants. The distribution of individual species of fen plants is often closely connected to water regimes and nutrient concentrations.

Forsyth–Edwards Notation (FEN) is a standard notation for describing a particular board position of a chess game. The purpose of FEN is to provide all the necessary information to restart a game from a particular position.

The renminbi is the official currency of the People's Republic of China. The name literally means "people's currency". The yuan  (sign: ¥) is the basic unit of the renminbi, but is also used to refer to the Chinese currency generally, especially in international contexts. The distinction between the terms renminbi and yuan is similar to that between sterling and pound, which respectively refer to the British currency and its primary unit. One yuan is subdivided into 10 jiao , and a jiao in turn is subdivided into 10 fen .