In the Christian calendar, Maundy Thursday is the English version of 'Holy Thursday,' the Thursday before Easter. It celebrates Jesus's last supper before his execution. Outside English-speaking countries it is universally known as Holy Thursday. Traditionally, it is the day when Jesus washed the feet of his disciples and told them to serve others as he served them. Consequently, in many churches, both Protestant and Roman Catholic, the priest or pastor washes the feet of his congregants on this day.
The Middle English word 'Maundy,' used only in this context, derives from Old French mandé from Latin mandamentum or 'commandment,' in reference to the opening words of the Catholic liturgy for this day, Mandatum novum do vobis 'a new commandment I give unto you' (John xiii:34), words spoken by Jesus to the Apostles after washing their feet in preparation for the Last Supper.
The day has also been known as Sheer Thursday, due to the idea that it is the day of cleaning (schere) and because the churches themselves would switch liturgical colors from the dark tones of Lent.
See also: Maundy money