ardor (n.)youdaoicibaDictYouDict[ardor 词源字典]
early 15c., "heat of passion or desire," from Old French ardure "heat, glow; passion" (12c.), from Latin ardorem (nominative ardor) "a flame, fire, burning, heat;" also of feelings, etc., "eagerness, zeal," from ardere "to burn" (see ardent). In Middle English, used of base passions; since Milton's time, of noble ones.[ardor etymology, ardor origin, 英语词源]