Source : Webster's Revised Unabridged Dictionary (1913)

Cathedra \Cath"e*dra\, n. [L., fr. Gr. ? seat. See {Chair}.]
   The official chair or throne of a bishop, or of any person in
   high authority.

   {Ex cathedra} [L., from the chair], in the exercise of one's
      office; with authority.

            The Vatican Council declares that the Pope, is
            infallible ``when he speaks ex cathedra.'' --Addis &
                                                  Arnold's Cath.
                                                  Dict.

Source : WordNet®

cathedra
     n : a throne that is the official chair of a bishop [syn: {bishop's
         throne}]