Today is Maundy Thursday and it seems only right that I've finally found out for Rachel why its called that, after many days of her asking.
The Latin basis of the word Maundy is Mandatum which means washing of feet. It is Jesus' washing of the disciples feet at the last supper that we celebrate and experience at Maundy Thursday services.
This is why we call today Maundy Thursday, because we re-enact The Maundy.
John 13:14-17 "If I then, your Lord and Teacher, have washed your feet, you also ought to wash one another’s feet." "For I have given you an example, that you should do as I have done to you." "Most assuredly, I say to you, a servant is not greater than his master; nor is he who is sent greater than he who sent him." "If you know these things, blessed are you if you do them."
Another thing I learned from my research is that there are quite a few other names for this day:
Thursday of Mysteries
For more details about what happens on Maundy Thursday at churches see my post from last year http://llmcalling.blogspot.co.uk/2011/04/maundy-thursday.html