Definition from Wiktionary, the free dictionary
maundy (plural maundies)
- (obsolete) A commandment.
- (obsolete) The sacrament of the Lord's supper.
- The ceremony of washing the feet of poor persons or inferiors, performed as a religious rite on Maundy Thursday in commemoration of Christ's washing the disciples' feet at the Last Supper.
- The office appointed to be read during the ceremony of feet-washing.
Derived terms 
- maundy in The Century Dictionary, The Century Co., New York, 1911