why is stan at the end of countries' names
The suffix-stan (Persian: ـستان ‎ ‎-stân) is Persian for "place of" or "country". It appears in the names of many regions, especially in Central and South Asia, but also in the Caucasus and Russia; areas where significant amounts of Persian culture were spread or adopted. The suffix is also used more generally, as in Persian, and Urdu rigestân (ریگستان) "place of sand, desert", Pakistan "land of the pure", Hindustan "land of the Indus river", golestân (گلستان) "place of flowers, garden", and in Bengali koborstan (কবরস্থান kabarasthāna) "graveyard / cemetery" etc.