Bright Week or Renewal Week is the name used by the Eastern Orthodox Church — and Eastern Catholic Churches of the Byzantine Rite — for the period of seven days beginning on Pascha (Easter) and continuing up to (but not including) the following Sunday, which is known as Thomas Sunday. Latin Rite and other Christian groups such as Anglicans refer to this period as Easter Week, not to be confused with the Octave of Easter, which includes the following Sunday.

Source:Church Calender