This is the 13th most frequent Persian word.
ایران
"Iran" - The name of a country in the Middle East.
Here, "ایران" is a proper noun used as the subject of the sentence to refer to the country Iran.
ایران یک کشور زیبا در خاورمیانه است.
Iran is a beautiful country in the Middle East.
In this sentence, "ایران" is a proper noun used as the object of the preposition "در" to specify the place where the living occurs.
من در ایران زندگی میکنم.
I live in Iran.
The word "ایران" here is used in a possessive structure to describe ownership or association (Iran's culture).