Noun
(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; maundy.
Part of the church service on Maundy Thursday is the pedilavium.
(chiefly medicine, obsolete) A footbath carried out for therapeutic purposes; a pediluvium.
Source: en.wiktionary.org