五ご辺へん形けいごへんけいMeanings1nounpentagonrare termgeometryRare geometry term for a five-sided polygon; 五角形 (ごかくけい) is the usual word.See also: 五角形五ご辺へん形けいは五ご角かく形けいと同おなじ意い味みだが、日にち常じょうではほとんど使つかわれない。五辺形 means the same as 五角形, but it is hardly ever used in everyday life.