CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 750–753

750 To believe that the Church is "holy" and "catholic," and that she is "one" and "apostolic" (as the Nicene Creed adds), is inseparable from belief in God, the Father, the Son, and the Holy Spirit. In the Apostles' Creed we profess "one Holy Church" (Credo . . . Ecclesiam), and not to believe in the Church, so as not to confuse God with his works and to attribute clearly to God's goodness all the gifts he has bestowed on his Church.
751 The word "Church" (Latin ecclesia, from the Greek ek-ka-lein, to "call out of") means a convocation or an assembly. It designates the assemblies of the people, usually for a religious purpose. Ekklesia is used frequently in the Greek Old Testament for the assembly of the Chosen People before God, above all for their assembly on Mount Sinai where Israel received the Law and was established by God as his holy people. By calling itself "Church," the first community of Christian believers recognized itself as heir to that assembly. In the Church, God is "calling together" his people from all the ends of the earth. The equivalent Greek term Kyriake, from which the English word Church and the German Kirche are derived, means "what belongs to the Lord."
752 In Christian usage, the word "church" designates the liturgical assembly, but also the local community or the whole universal community of believers. These three meanings are inseparable. "The Church" is the People that God gathers in the whole world. She exists in local communities and is made real as a liturgical, above all a Eucharistic, assembly. She draws her life from the word and the Body of Christ and so herself becomes Christ's Body.
753 In Scripture, we find a host of interrelated images and figures through which Revelation speaks of the inexhaustible mystery of the Church. The images taken from the Old Testament are variations on a profound theme: the People of God. In the New Testament, all these images find a new center because Christ has become the head of this people, which henceforth is his Body. Around this center are grouped images taken "from the life of the shepherd or from cultivation of the land, from the art of building or from family life and marriage."