grey matter grey market • grey mullet · · · Info · Definitions · Synonyms · Characters · · grey matter · · Text Common · · Latin · · Scripts 11 · · Length 4 · · Syllables Definitions · · · (noun) greyish nervous tissue containing cell bodies as well as fibers; forms the cerebral cortex consisting of unmyelinated neurons. Synonyms: grey matter, gray matter, grey substance, gray substance, substantia grisea. · · Noun Definition 1 Synonyms · · · gray matter · · Synonym 1 grey substance · · Synonym 2 gray substance · · Synonym 3 substantia grisea · · Synonym 4 Characters · · space U+0020 a latin small letter a U+0061 e latin small letter e U+0065 g latin small letter g U+0067 m latin small letter m U+006D r latin small letter r U+0072 t latin small letter t U+0074 y latin small letter y U+0079