Catechism of the Catholic Church §811 — excerpt
"This is the sole Church of Christ, which in the Creed we profess to be one, holy, catholic and apostolic." These four characteristics, inseparably linked with each other, indicate essential features of the Church and her mission.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: LG 8 · DS 2888