odor

Middle English odour, borrowed from Anglo-French odur, borrowed from Latin odor (early Latin odōs), going back to *od-os-, s-stem derivative of a verbal base *od- (whence Latin oleō, olēre, also olō, olere "to give off a smell, smell (of)," from *odere), going back to Indo-European *h₃ed-, whence Greek ózein "to smell, give off an odor," Armenian hot "smell, odor" (probably also an s-stem), Lithuanian úodžiu, úosti "to smell, sniff"

Note: The length in the Baltic form is attributed to Winter's Law, which is believed to lengthen vowels before an original voiced, unaspirated stop in Baltic and Slavic in certain environments.