maundy: [13] Maundy Thursday commemorates Christ’s washing of the apostles’ feet at the Last Supper. The first antiphon sung at the Catholic Maundy service begins Mandātum novum dō vōbis ‘I give you a new commandment’, and so in medieval Latin mandātum (source of English mandate) came to be used as the name for the commemorative ceremony. The word passed into Old French as mandé, whence English maundy. => mandate, manual
