Catechism of the Catholic Church §1523 — excerpt
A preparation for the final journey. If the sacrament of anointing of the sick is given to all who suffer from serious illness and infirmity, even more rightly is it given to those at the point of departing this life; so it is also called sacramentum exeuntium (the sacrament of those departing).
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: Council of Trent (1551): DS 1698 · Council of Trent (1551): DS 1694