§774

The Greek word mysterion was translated into Latin by two terms: mystenum and sacramentum. In later usage the term sacramentum emphasizes the visible sign of the hidden reality of salvation which was indicated by the term mystenum. In this sense, Christ himself is the mystery of salvation: "For there is no other mystery of God, except Christ." The saving work of his holy and sanctifying humanity is the sacrament of salvation, which is revealed and active in the Church's sacraments (which the Eastern Churches also call "the holy mysteries"). The seven sacraments are the signs and instruments by which the Holy Spirit spreads the grace of Christ the head throughout the Church which is his Body. The Church, then, both contains and communicates the invisible grace she signifies. It is in this analogical sense, that the Church is called a "sacrament."