雲くもの海うみMeanings1nounSea of Clouds; Mare NubiumProper noun for a lunar mare; used in astronomical contexts.雲くもの海うみは月つきの南みなみ半はん球きゅうにある大おおきな暗くらい平へい原げんです。The Sea of Clouds is a large dark plain in the southern hemisphere of the Moon.