The answer to the question can be a little confusing because “Maundy Thursday” is also known in various parts of the world as “Holy Thursday,” “Covenant Thursday,” “Great and Holy Thursday,” “Thursday of Mysteries,” and “Sheer Thursday.” – (re Wikipedia)

An easy definition would be Maundy Thursday is a Christian feast [for those who observe it], or a holy day, falling on the Thursday before Easter.  It is also identified as the day on which Jesus celebrated the Passover with His disciples, known as the Last Supper.  The date is the fifth of Holy Week and is preceded by Holy Wednesday and followed by Good Friday.  The date is always between 19 March and 22 April inclusive.  The date may fall on different days depending on whether the Gregorian or Julian calendar is used liturgically.

According to Wikipedia, Eastern churches generally use the Julian calendar and so celebrated this feast throughout the 21st century between 1 April and 5 May.  Others more commonly use the Gregorian calendar.

The liturgy held on the evening of Maundy Thursday initiates the Easter Triduum, the period which commemorates the passion, death, and resurrection of Christ; this period includes Good Friday, Holy Saturday, and ends on the evening of Easter.  The Mass or service of worship is normally celebrated in the evening, when Friday begins according to Jewish tradition; the Last Supper was held on feast of Passover.

Notice two things:

  1. Jesus celebrated the Last Supper with His disciples and thereby instituted the Lord’s Supper, also called communion(Luke 22:19-20; I Corinthians 11:23ff.).

Some Christian churches observe a special Communion Service on Maundy Thursday in memory of Jesus’ Last Supper   with His disciples.

2.  Jesus washed the disciples’ feet as an act of humility and service, thereby setting an example that we should love and serve one another in humility (John 13:3-17; 34-35).  Also, some Christian churches observe a foot-washing ceremony on Maundy Thursday to commemorate Jesus’ washing the feet of the disciples.

Definition of the word “Maundy”:  The word is derived from the Latin word for “command.”  The  “Maundy”  in Maundy Thursday refers to the command Jesus gave to His disciples at the Last Supper, that they should love and serve one another (see John 13:34-35).

Good question:  Should Christians observe Maundy Thursday?  The answer is simple:  the Bible neither forbids it nor commands the Christian to observe Maundy Thursday.  The command for the Christian is to observe what is called “communion,” found in I Corinthians 11:23ff.).

However, Maundy Thursday could be a good time to remind us of the example of humility given by Christ at the Last Supper.  Further, it is also always good to think about the sacrifice of Christ on our behalf even though at communion we go into that area in some detail.  We might go further and indicate it might be good for Christians to remember that we are supposed to be an humble people and on Maundy we have an outstanding example.  It helps to remind ourselves from time to time of how God is pleased when His people get concerned over pride.

Caution:  We should avoid establishing a ritualistic observance unless it is truly focused on God and our relationship with Him.