calculation (n.)youdaoicibaDictYouDict[calculation 词源字典]
late 14c., from Late Latin calculationem (nominative calculatio), noun of action from past participle stem of calculare "to reckon, compute," from Latin calculus "reckoning, account," originally "pebble used in counting," diminutive of calx (genitive calcis) "limestone" (see chalk (n.)).[calculation etymology, calculation origin, 英语词源]