The encyclical is a teaching letter of the Pope of very high rank. In it the Pope comments on theological and social questions. An encyclical does not have the status of infallibility, yet it is an expression of the supreme teaching power of the Pope, expresses a judgement on so far controversial questions and withdraws them from the free discussion of theology (according to Pope Pius XII). The term derives from the Greek enkyklios, which means running in a circle. Encyclicals are thus circulars to the entire Roman Catholic Christendom. The first explicit encyclical was published in 1740 and dealt with the official duties of the bishops.
German: Enzyklika (308)
Source: Kathweb m. e. E., 30.05.2019