Meaningcave · den · excavationOn'yomiドウKun'yomiほらCommon compounds (6)空洞 くうどうhollow洞察 どうさつdiscernment; insight洞窟 どうくつcave; cavern; grotto洞穴 どうけつcave; cavern; den; grotto鍾乳洞 しょうにゅうどうlimestone cave; limestone cavern風洞 ふうどうwind tunnel