attenuation (n.)youdaoicibaDictYouDict[attenuation 词源字典]
early 15c., of persons, "emaciation;" of diet, "reduction," from Latin attenuationem (nominative attenuatio) "a lessening," noun of action from past participle stem of attenuare (see attenuate).[attenuation etymology, attenuation origin, 英语词源]