The fen (Chinese: 分; pinyin: fēn) in Mandarin, fan in Cantonese or hun in Taiwanese, is a traditional Chinese unit of length. One fen equals 1/10 of a cun or 1/100 of a chi. It is 3+1⁄3 mm in China mainland, 3.71475 mm in Hong Kong and 3.030 mm in Taiwan.
[1][2]
China mainland
Table of Chinese length units effective since 1930[3]
These correspond to the measures listed simply as "China" in The Measures, Weights, & Moneys of All Nations[6]
Taiwan
Length measure in Taiwan is largely metric but some units derived from traditional Japanese units of measurement remain in use as a legacy of Japanese rule.[7]
Table of Traditional Chinese Length Units since 1930
Taiwanese length units and the translation of length units in metric system (SI) shares the same character. The adjective Taiwanese (台) can be added to address the Taiwanese unis system. For example, 台尺 means Taiwanese foot and 公尺 means meter.
Compounds
"分寸" is a Chinese word which literally means fen and cun, two traditional Chinese units of length; figuratively, it refers to the sense of propriety, or the proper degree for saying or doing something. For example, "说话要注意分寸。" (Pay attention to the sense of propriety in speaking.)[8][9]