diencephalon diencephalic • diene · · · Info · Definitions · Synonyms · Characters · · diencephalon · · Text Latin · · Script 12 · · Length Definitions · · · (noun) the posterior division of the forebrain; connects the cerebral hemispheres with the mesencephalon. Synonyms: interbrain, betweenbrain, thalmencephalon. · · Noun Definition 1 Synonyms · · · interbrain · · Synonym 1 betweenbrain · · Synonym 2 thalmencephalon · · Synonym 3 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E o latin small letter o U+006F p latin small letter p U+0070