ENCYCLICAL (from Late Lat. encyclicus, for encyclius = Gr., from and , "a circle"), an ecclesiastical epistle intended for general circulation, now almost exclusively used of such letters issued by the pope. The forms encyclica and encyclic are sometimes, but more rarely, used. The old adjectival use of the word in the sense of "general" (encircling) is now obsolete, though it survives in the term "encyclopaedia."
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)