The Collaborative International Dictionary of English v.0.48:

Oral \O"ral\, a. [L. os, oris, the mouth, akin to Skr. [=a]s.
   Cf. Adore, Orison, Usher.]
   1. Uttered by the mouth, or in words; spoken, not written;
      verbal; as, oral traditions; oral testimony; oral law.
      [1913 Webster]

   2. Of or pertaining to the mouth; surrounding or lining the
      mouth; as, the oral cavity; oral cilia or cirri.
      [1913 Webster]

WordNet (r) 3.0 (2006):

oral
    adj 1: using speech rather than writing; "an oral tradition";
           "an oral agreement" [syn: oral, unwritten]
    2: of or relating to or affecting or for use in the mouth; "oral
       hygiene"; "an oral thermometer"; "an oral vaccine"
    3: of or involving the mouth or mouth region or the surface on
       which the mouth is located; "the oral cavity"; "the oral
       mucous membrane"; "the oral surface of a starfish" [ant:
       aboral]
    4: a stage in psychosexual development when the child's interest
       is concentrated in the mouth; fixation at this stage is said
       to result in dependence, selfishness, and aggression [ant:
       anal, anal retentive]
    n 1: an examination conducted by spoken communication [syn:
         oral, oral exam, oral examination, viva voce,
         viva]

Moby Thesaurus II by Grady Ward, 1.0:

97 Moby Thesaurus words for "oral":
   acknowledged, admitted, answering, articulate, articulated,
   audition, blue book, communicating, communicational, communional,
   conventional, conversational, customary, enunciated, established,
   exam, examen, examination, final, final examination, fixed, folk,
   great go, hallowed, handed down, hearing, heroic, hoary, honors,
   immemorial, interacting, interactional, interactive,
   intercommunicational, intercommunicative, intercommunional,
   interresponsive, interrogative, interrogatory, inveterate,
   legendary, lingual, linguistic, long-established, long-standing,
   mandibular, maxillary, midsemester, midterm, mouthlike,
   mythological, nuncupative, of long standing, of the folk,
   oral examination, orificial, parol, prelim, prescriptive,
   pronounced, questioning, quiz, received, recognized, responsive,
   rooted, said, sonant, sounded, speech, spoken,
   take-home examination, telepathic, test, time-honored, told,
   traditional, transmissional, trial, tried and true, tripos,
   true-blue, understood, unwritten, uttered, venerable, verbal, viva,
   viva voce, vocal, vocalized, voiced, voiceful, word-of-mouth,
   worshipful, written, written examination



Bouvier's Law Dictionary, Revised 6th Ed (1856):

ORAL. Something spoken in contradistinction to something written; as oral
evidence, which is evidence delivered verbally by a witness,