great warmth of feeling; fervor; passion: She spoke persuasively and with ardor.
intense devotion, eagerness, or enthusiasm; zeal: his well-known ardor for Chinese art.
Also, especially British,ardour.
Origin: 1350–1400;Middle English < Latin, equivalent to ārd(ēre) to burn + -or-or1; replacing Middle Englishardure < Old Frenchardur < Latin, as above; 17th century ardour < Anglo-French < Latin, as above
late 14c., "heat of passion or desire," from O.Fr. ardour (12c.), from L. ardorem (nom. ardor) "a flame, fire," from ardere "to burn" (see ardent). In M.E., used of base passions; since Milton's time, of noble ones.