hornfels hornfair • hornfish · · · Info · Definitions · Synonyms · Characters · · hornfels · · Text Latin · · Script 8 · · Length Definitions · · · (noun) a fine-grained metamorphic rock formed by the action of heat on clay rocks. Synonyms: hornstone. · · Noun Definition 1 Synonyms · · · hornstone · · Synonym 1 Characters · · e latin small letter e U+0065 f latin small letter f U+0066 h latin small letter h U+0068 l latin small letter l U+006C n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073