"The English word "maundy" is derived from the Latin word mandatum, which is the Vulgate's translation of Jesus 'words in John 13: 34: "A new commandment I give unto you, that you love one another.""
""Maundy" comes from the word "mandatum," the "new commandment" to love one another that Jesus made at the Last Supper, as recorded in the Bible's John 13:34."
"Maundy Thursday takes its name from the Latin word "mandatum," the root of the English word mandate, according to the Catholic Encyclopedia."