Maundy Thursday

The word "Maundy" comes from the Latin for 'command' (mandatum). It refers to the command given by Jesus at the Last Supper, that his disciples should love one another.

and from www.howstuffworks.com website:
"The word "maundy" may have come from the maund (or mand) basket used by the fishermen in the English counties of Norfolk and Suffolk. Centuries ago, there was a fair held on this day in Norwich (Norfolk), at which vendors sold horses, cattle and general merchandise. Some of the fisher-folk brought their maund baskets filled with items to sell, including fish. Clothing and hats were sold, as it was customary to buy a new item of clothing for Easter Sunday. This may well have been the origin of the Easter bonnet and the notion of wearing new spring attire for Easter.
Maundy Thursday may also have come from the Latin word mandatum, meaning "commandment," as in the Biblical words of Jesus:
"A new command I give you. Love one another. As I have loved you, so you must love one another." (John 13:34, NIV)
Many Maundy Thursday services begin with these words."