open seaWiktionary 原文英美构词拆解open词干+sea词干词源链中古英语Middle English约 1150–1500 年open see↓ 继承英语Englishopen sea词源说明From Middle English open see, open se, equivalent to open + sea.释义名词noun1That part of the sea out of sight of land.2A sea open to all nations, i.e. not a mare clausum.