Question

how has the term hindustan changed over time

Answer 1

The meaning of the term “Hindustan” changed over the centuries:
In the 13th century, Minhaj-i-Siraj wrote the Persian used “Hindustan” in the political sense for lands, that was the part of the dominions of the Delhi Sultan.
In the 14th century, the poet Amir Khusrau used the “Hindi” word for the people and culture of the Indus river.
In the 16th century, Babur used the word to describe the geography.