What is the X in X-mas?
c.1300, from Anglo-French odour, from Old French odor "smell, perfume, fragrance" (12c., Modern French odeur) and directly from Latin odor "a smell, a scent" (pleasant or disagreeable), from PIE *od- "to smell" (cf. Latin olere "emit a smell, to smell of," with Sabine -l- for -d-; Greek ozein "to smell;" Armenian hotim "I smell;" Lithuanian uodziu "to smell").
Good or bad odor, in reference to repute, estimation, is from 1835. Odor of sanctity (1756) is from French odeur de sainteté (17c.) "sweet or balsamic scent said to be exhaled by the bodies of eminent saints at death or upon disinterment."
odor o·dor (ō'dər)
The property or quality of a thing that affects, stimulates, or is perceived by the sense of smell.
A sensation, stimulation, or perception of the sense of smell.
the property of certain substances, in very small concentrations, to stimulate chemical sense receptors that sample the air or water surrounding an animal. In insects and other invertebrates and in aquatic animals, the perception of small chemical concentrations often merges with perception via contact of heavy concentrations (taste), and with other chemoreceptive specializations. See also smell.