In the Orthodox Church the last week of Christ's life is officially
called Passion Week. In popular terminology it is called Holy Week.
Each day is designated in the service books as "great and holy." There
are special services every day of the week which are fulfilled in all
churches. Earthly life ceases for the faithful as they "go up with the
Lord to Jerusalem" (Matins of Great and Holy Monday). -Taken from Fr. Hopko's series The Orthodox Faith.