CATHEDRA
cathedra, bishop's throne
(noun) a throne that is the official chair of a bishop
Source: WordNet® 3.1
Etymology
Noun
cathedra (plural cathedrae or cathedras)
The chair or throne of a bishop.
The rank of bishop.
The official chair of some position or office, as of a professor.
Source: Wiktionary
Cath"e*dra, n. Etym: [L., fr. Gr. Chair.]
Definition: The official chair or throne of a bishop, or of any person in
high authority. Ex cathedra Etym: [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: Webster’s Unabridged Dictionary 1913 Edition