accumulation (n.)youdaoicibaDictYouDict[accumulation 词源字典]
late 15c., from Latin accumulationem (nominative accumulatio) "a heaping up," noun of action from past participle stem of accumulare "to heap up, amass," from ad- "in addition" (see ad-) + cumulare "heap up," from cumulus "heap" (see cumulus).[accumulation etymology, accumulation origin, 英语词源]