It is mostly used as a place suffix, as you mentioned, some times indicates the affluence of that noun (in that place of course). for example: golestan / گلستان / means rosary or a place that has plentiful flowers "gol". some times indicates just the place of something. like: farhangestan / فرهنگستان / means academy or a place of study or training. if you use it with a "Proper Noun" it indicates the seat of that noun. As: Turkestan / ترکستان / means the place that Turkish guys settled. and some times used as a time suffix: tabestan / تابستان / which means summer but generally you can consider it as a place suffix. hope to be useful.

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