An oral exam undertaken to defend ones Doctoral Thesis in the sciences (and perhaps in other subjects). Usually
a formality, however if the faculty or the external examiner is unhappy with the work the viva may let the student prove
that they deserve the degree. However it is not such a formality that it is impossible to fail. The objective of the viva is to prove to the examining board that the content of the thesis is an origianl work of quality, is work undertaken by the student and that the student understands fully the content and the related science. Viva is short for Viva voce.