Bright Week shortly explained

Bright Week, Pascha Week or Renewal Week (Greek: Διακαινήσιμος Ἑβδομάς) is the name used by the Eastern Orthodox and Byzantine Rite Catholic Churches for the period of seven days beginning on Easter and continuing up to (but not including) the following Sunday, which is known as Thomas Sunday.

Bright Week – Wikipedia

https://en.m.wikipedia.org/wiki/Bright_Week

Bright Week, Pascha Week or Renewal Week (Greek: Διακαινήσιμος Ἑβδομάς) is the name used by the Eastern Orthodox and Byzantine Rite Catholic Churches for the period of seven days beginning on Easter and continuing up to (but not including) the following Sunday, which is known as Thomas Sunday.