Paragraph 31 of the dogmatic constitution Lumen Gentium:
The term laity is here understood to mean all the faithful except those in holy orders and those in the state of religious life specially approved by the Church. These faithful are by baptism made one body with Christ and are constituted among the People of God; they are in their own way made sharers in the priestly, prophetical, and kingly functions of Christ; and they carry out for their own part the mission of the whole Christian people in the Church and in the world.