Catechism of the Catholic Church §455 — excerpt
The title "Lord" indicates divine sovereignty. To confess or invoke Jesus as Lord is to believe in his divinity. "No one can say 'Jesus is Lord' except by the Holy Spirit'" (I Cor 12:3).
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.