E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Infallibility (of the Church of Rome)
is the doctrine that the Church of Rome cannot at any time cease to be orthodox in her doctrine, and that what she declares ex cathedrâ is substantially true. The doctrine is based on the Divine promise to the disciples, Howbeit when the Spirit of Truth is come, he will guide you into all truth (John xvi. 13).
The dogma of the Infallibility of the Pope was decreed by the Vatican Council in 1870.