An encyclical letter is a type of papal document that is addressed to bishops, priests, and the Catholic faithful. This document aims to provide guidance, teachings and instructions on matters related to faith, morality, and social justice. Synonyms for encyclical letter include papal bull, apostolic letter, pastoral letter, exhortation, and encyclical memorandum. While these terms may have slightly different meanings and purposes, they all serve as official communications from the Pope meant to provide insight and guidance for Catholics around the world. These documents are often considered significant and important sources of Catholic teaching and tradition.