Ar"dor (&?;), n. [L. ardor, fr. ardere to burn: cf. OF. ardor, ardur, F. ardeur.] [Spelt also ardour.] 1. Heat, in a literal sense; as, the ardor of the sun's rays.
2. Warmth or heat of passion or affection; eagerness; zeal; as, he pursues study with ardor; the fought with ardor; martial ardor.