Source : Webster's Revised Unabridged Dictionary (1913)

Viva voce \Vi"va vo"ce\ (v>imac/"v[.a] v[=o]"s[-e]). [L.]
   By word of mouth; orally.

Source : WordNet®

viva voce
     n : an examination conducted by word of mouth [syn: {oral}, {oral
         exam}, {oral examination}, {viva}]
     adv : orally; "I heard it viva voce" [syn: {by word of mouth}]