oscitant adj.

1620s, "uttered by the mouth or in words;" 1650s, "of or pertaining to the mouth," from Late Latin oralis, from Latin os (genitive oris) "mouth, opening, face, entrance," from PIE *os- "mouth" (source also of 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").

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 colloquially as "mouth," became the usual word for "mouth" (see bouche).

The psychological meaning "of the mouth as the focus of infantile sexual energy" (as in oral fixation) is attested from 1910. The sex-act sense is first recorded 1948, in Kinsey. As a noun, "oral examination," attested from 1876. Related: Orally (c. 1600); orality. 

mid-15c., "to summon, call upon officially," from Old French citer "to summon" (14c.), from Latin citare "to summon, urge, call; put in sudden motion, call forward; rouse, excite," frequentative of ciere "to move, set in motion, stir, rouse, call, invite" from PIE root *keie- "to set in motion, to move to and fro."

Sense of "call forth a passage of writing, quote the words of another" is first attested 1530s. Related: Cited; citing.