This solemn service commemorates the events of the night before Jesus' crucifixion: the Last Supper, the institution of the Eucharist, and Jesus washing the disciples' feet.
The word "Maundy" comes from Latin mandatum, meaning "commandement", referring to Jesus' words:
"I give you a new commandment, that you love one another. Just as I have loved you, you also should love one another." John 13:34