myelin myelic • myelinate · · · Info · Definitions · Synonyms · Characters · · myelin · · Text Latin · · Script 6 · · Length Definitions · · · (noun) a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers. Synonyms: myeline, medulla. · · Noun Definition 1 Synonyms · · · myeline · · Synonym 1 medulla · · Synonym 2 Characters · · e latin small letter e U+0065 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D n latin small letter n U+006E y latin small letter y U+0079