oral (adj.) Look up oral at Dictionary.com
1620s, from Late Latin oralis, from Latin os (genitive oris) "mouth, opening, face, entrance," from PIE *os- "mouth" (cognates: Sanskrit asan "mouth," asyam "mouth, opening," Avestan ah-, Hittite aish, Middle Irish a "mouth," Old Norse oss "mouth of a river," Old English or "beginning, origin, front"). Psychological meaning "of the mouth as the focus of infantile sexual energy" (as in oral fixation) is from 1910. The sexual sense is first recorded 1948, in Kinsey. As a noun, "oral examination," attested from 1876. Related: Orally (c.1600); orality.