Christians mark Maundy Thursday, which commemorates the Last Supper, every year on the Thursday before Easter, April 9. It’s also know as Holy Thursday, Covenant Thursday, and the Thursday of Mysteries in various traditions.
Maundy refers to the foot-washing Jesus provided the apostles prior to the Last Supper. Christians around the world, especially Catholics, mark the day with a special mass and prayers.
The word “Maundy” itself comes from an Anglo-French word derived from the Latin “mandatum,” which means “commandment.”