oralyoudaoicibaDictYouDict
oral: [17] Oral comes from Latin ōs ‘mouth’. This went back to a prehistoric Indo-European *ōs- or *ōus-, which also produced Sanskrit ās-, ‘mouth’ and Old Norse óss ‘mouth of a river’. Its other contributions to English include orifice [16] (etymologically ‘forming a mouth’), oscillate, osculate ‘kiss’ [17], and usher.
=> orifice, oscillate, osculate, usher
oral (adj.)youdaoicibaDictYouDict
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. Os was the usual word for "mouth" in Latin, but as the vowel distinction was lost it became similar in sound to os "bone" (see osseous). Thus bucca, originally "cheek" but used colloquial as "mouth," because the usual word for "mouth" (see bouche).