sinkhole sinkhead • sinking · · · Info · Definitions · Synonyms · Characters · · sinkhole · · Text Latin · · Script 8 · · Length Definitions · · · (noun) a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof. Synonyms: sink, swallow hole. · · Noun Definition 1 Synonyms · · · sink · · Synonym 1 swallow hole · · Synonym 2 Characters · · e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 k latin small letter k U+006B l latin small letter l U+006C n latin small letter n U+006E o latin small letter o U+006F s latin small letter s U+0073