Original: The Shi'ite or Shi'a Crescent is a recent geo-political term used to describe a region of the Middle East where the majority population is Shi'a, or where there is a strong Shi'a minority in the population.
Simplified: Shiite Crescent is  used as political and geo-political term to descripe the different countries who's majority is shia or who had a strong shia minority in the population.