- Heat, in a literal sense; as, the ardor of the sun's rays.
- Warmth or heat of passion or affection; eagerness; zeal; as, he pursues study with ardor; the fought with ardor; martial ardor.
- pl.Bright and effulgent spirits; seraphim.(Thus used by Milton)synonyms: Fervor; warmth; eagerness. See Fervor.
Etymology: L. ardor, fr. ardere to burn: cf. OF. ardor ardur, F. ardeur