Thursday before Easter, mid-15c., from Middle English maunde "the Last Supper" (c. 1300), also "ceremony of washing the feet of poor persons or inferiors, performed as a religious rite on Maundy Thursday" (early 14c.), from Old French mandé, from Latin mandatum "commandment" (see mandate (n.)); said to be so called in reference to the opening words of the Latin church service for this day, Mandatum novum do vobis "A new commandment I give unto you" (John xiii:34), words supposedly spoken by Jesus to the Apostles after washing their feet at the Last Supper.