transmittance transmittal • transmittancy · · · Info · Definitions · Synonyms · Characters · · transmittance · · Text Latin · · Script 13 · · Length Definitions · · · (noun) the fraction of radiant energy that passes through a substance. Synonyms: transmission. · · Noun Definition 1 Synonyms · · · transmission · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074