pedilavium : (Christianity) The rite of foot-washing based on the act carried out by Jesus Christ on his disciples at the Last Supper. Depending on the church or denomination, it may be carried out at baptism, during Holy Communion, or as part of a Maundy Thursday service. (chiefly medicine, obsolete) A footbath carried out for therapeutic purposes; a pediluvium. Today is Maundy Thursday in both Eastern and Western Christianity in 2017. It commemorates the maundy (foot-washing) which Jesus Christ performed on his disciples, and the Last Supper which they shared, the night before his crucifixion and death.