c. 1300, "sweet smell, scent, fragrance," 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 root *hed- "to smell" (source also of Latin olere "emit a smell, to smell of," with Sabine -l- for -d-; Greek ozein "to smell," odmē "odor, scent;" Armenian hotim "I smell;" Lithuanian uodžiu, uosti "to smell, sniff;" Old Czech jadati "to investigate, explore").

Neutral sense of "smell as an inherent property of matter; scent or fragrance whether pleasant or not" is from late 14c. "[W]hen used without a qualifying adjunct, the word usually denotes an agreeable smell" [Century Dictionary, 1895]. Good or bad odor, in reference to repute or esteem, 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." In Middle English odor also had a figurative sense of "spiritual fragrance of Christ's sacrifice." 

"fragrant, emitting a smell or scent," early 15c., from Medieval Latin odorosus, from Latin odorus "having a smell," from odor "a smell, a scent" (see odor). Related: Odorously; odorousness.

"having a good sense of smell, having well-developed olfactory organs," 1878, from French osmatique, apparently coined by Paul Broca, from Greek osmē "smell, scent, odor" from PIE root *hed- "to smell" (see odor). Related: Anosmatic.

1848, "a deodorizer," originally of substances to quell the odor of manure, formed in English as if from de- + Latin odorantem, from odor "smell" (see odor (n.)). In reference to a substance to be used on the human body, from 1860. An earlier version, a perfumed powder, was called empasm (1650s), from Greek *empasma "to sprinkle on."

"sense of smell, faculty of smelling," 1846, noun of action from Latin olfactus, past participle of olfacere "to smell, get the smell of" (transitive), from olere "to emit a smell" (see odor) + facere "to make" (from PIE root *dhe- "to set, put").

modified form of oxygen, 1840, from German Ozon, coined in 1840 by German chemist Christian Friedrich Schönbein (1799-1868) from Greek ozon, neuter present participle of ozein "to smell" (see odor). So called for its pungent odor. Related: Ozonic.

"loss of sense of smell," 1811, Modern Latin, from Greek an- "not, without" (see an- (1)) + osmē "smell" (Doric odmē), from *odsme, from PIE root *hed- "to smell" (see odor) + abstract noun ending -ia.

"making or causing to smell; having the sense of smell," 1650s, from Latin olfactorius, from olfact-, past-participle stem of olfacere "to get the smell of, sniff," from olere "emit a smell, give off a smell of" (see odor) + facere "to make" (from PIE root *dhe- "to set, put").