Where does “нишастан” come from?

нишастан (Tajik) comes from Persian نشستن, from Middle Persian nšstn', from Proto-Iranian ni-, from Proto-Indo-Iranian ní, from Proto-Indo-European ni — down.

нишастан (Tajik): to sit

Definitions

to sit

Ancestry of “нишастан”, step by step

Step	Language	Word	Meaning
1	Persian	نشستن	to sit
2	Middle Persian	nšstn'	sit on
3	Proto-Iranian	ni-	down
4	Proto-Indo-Iranian	ní	down, downwards; in, into
5	Proto-Indo-European	ni	down

Every word from Proto-Indo-European ni →Every word from Proto-Indo-Iranian ní →Every word from Proto-Iranian ni- →