noun
- a Latin hymn on the Day of Judgment, commonly sung in a Requiem Mass.
noun
- Christianity a famous Latin hymn of the 13th century, describing the Last Judgment. It is used in the Mass for the dead
- a musical setting of this hymn, usually part of a setting of the Requiem
literally “day of wrath,” first words of Latin hymn of Last Judgment, attributed to Thomas of Celano (c.1250). See diurnal + ire.