-stan

The suffix -stan is formed from the old Iranian root *sta- "to stand, stay" (related to English "stand" and "stay") and means "place where one stays," i.e. homeland or country.  Names such as Afghani-stan, Tajiki-stan, Turkmeni-stan, Uzbeki-stan are formed by adding this suffix to the usually pluralized names of the people living in that country, as the Afghani (one Afghan) live in Afghanistan.  However, Pakistan was formed from the initial letters of "Punjab," "Afghanistan," and "Kashmir" and the questionably extended suffix -istan.  So, now there is an extended suffix floating around that may be added to new countries, the name of whose people is not pluralized by the suffix -i.