"Laudato SI" is the title of the second encyclical written by Pope Francis, which falls under the subject of Catholic social teaching. The phrase "Laudato SI" is in Latin and translates to "Praise be to you" in English. It's named after the opening words of the encyclical, which is a common practice in Catholic documents.(Brave Leo)

In his second encyclical, "Laudato Si': On Care for Our Common Home", Pope Francis draws all Christians into a dialogue with every person on the planet about our common home. We as human beings are united by the concern for our planet and every living thing that dwells on it, especially the poorest and most vulnerable. Pope Francis' letter joins the body of the Church's social and moral teaching and draws on the best scientific research, providing the foundation for "the ethical and spiritual itinerary that follows".