In Catholic theological language, “dogma” refers to doctrines that have an “absolute value and are unquestionable.” The exact definition of papal infallibility, as approved by the council of 1870, states:

“It is a divinely revealed dogma that the Roman pontiff, when he speaks ex cathedra, that is, when acting in the office of shepherd and teacher of all Christians, he defines, by virtue of his supreme apostolic authority, a doctrine concerning faith or morals to be held by the universal church, possesses through the divine assistance promised to him in the person of blessed Peter, the infallibility with which the divine Redeemer willed his church to be endowed in defining the doctrine concerning faith or morals; and that such definitions of the Roman pontiff are therefore irreformable of themselves, not because of the consent of the church.”

“Infallibility” means, then, that the pope, even though he makes mistakes like all other humans, does not err when defining matters of faith and morals ex cathedra, acting in the office of shepherd of the Roman Catholic Church.