Word: 溶洞 (róngdòng) 溶洞 dictionary entry róngdòng solutional cave (typically, a limestone cave) Full dictionary entry for 溶洞 Example sentences using 溶洞 2 sentences, showing page 1 of 1. 导游带着大家走进了山里的溶洞。 Dǎoyóu dàizhe dàjiā zǒujìnle shān lǐ de róngdòng. The guide led everyone into the karst cave in the mountain. 溶洞里面又黑又冷，带件外套吧。 Róngdòng lǐmiàn yòu hēi yòu lěng, dài jiàn wàitào ba. It's dark and cold inside the cave, so bring a jacket.