summation (n.)youdaoicibaDictYouDict[summation 词源字典]
1760, "process of calculating a sum," from Modern Latin summationem (nominative summatio) "an adding up," noun of action from Late Latin summatus, past participle of summare "to sum up," from Latin summa (see sum (n.)). Meaning "a summing up" is from 1836.[summation etymology, summation origin, 英语词源]