“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.139 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.140 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,141 but also the local community142 or the whole universal community of believers.143 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.”
If a church is “the assemblies of the people, usually for a religious purpose,” then a church that raises the mind to the God of that religion and therefore to the religion itself is an effective church. The fact that the word “Kyriake, from which the English word Church and the German Kirche are derived, means ‘what belongs to the Lord,'” shows that a church should center thought on God, His attributes, and what is His.
Excerpt from ARTICLE 9 “I BELIEVE IN THE HOLY CATHOLIC CHURCH”, Paragraph 1. The Church in God’s Plan, I. NAMES AND IMAGES OF THE CHURCH from the Catechism of the Catholic Church