SJ is a written short form that comes after a Catholic priest’s name. It tells you he belongs to the Jesuits — a big group of priests and brothers in the Catholic Church, whose Latin name is Societas Jesu, “the Society of Jesus.” You usually see it in print, not in casual chat: Fr. James Martin, SJ. People do not normally say the letters out loud unless they are reading a list; even then they just say the letters, “S.J.” It is a label of which order he is in, not a rank and not a saint’s title. Jesuit priests are known for schools, universities, and missionary work, so you will meet SJ a lot on church notices, book covers, and school staff lists.