Where does “nȍzdrь” come from?

nȍzdrь (Proto-Slavic) comes from Proto-Slavic nȍsъ, from Proto-Balto-Slavic nasús, from Proto-Indo-European néh₂s- — nose, nostril.

Ancestry of “nȍzdrь”, step by step

nȍzdrь traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Proto-Slavic	nȍsъ	nose
2	Proto-Balto-Slavic	nasús	nose
3	Proto-Indo-European	néh₂s-	nose, nostril

Step	Language	Word	Meaning
1	Proto-Slavic	dьràti	to tear, to flay; to tear, to flay; to cut into...
2	Proto-Indo-European	der-	to split, to separate; to tear, to crack, to...