As a Noun: 1. The set of Christian beliefs that are held by people who belong to the branch of the church which accepts the Pope as its leader. English = Catholicism. 2. A person who belongs to the branch of the Christian church which accepts the Pope as its leader. English = Catholic. 3. A person who believes in Jesus Christ and follows his teachings. (Particularly used by Catholics in this sense.) English = Christian. As a Verb or Adjective: 1. To have the set of Christian beliefs of people who belong to the branch of the church which accepts the Pope as its leader. English = (be) Catholic. 2. To be a person who belongs to the branch of the Christian church which accepts the Pope as its leader. English = (be) Catholic. 3. To be person who believes in Jesus Christ and follows his teachings. (Particularly used by Catholics in this sense.) English = (be) Christian.