srodstvo

1. kinship; family relationship
   U kakvom ste srodstvu vas dvoje? — How are you two related?
   Između nas nema nikakvog srodstva. — We're not related at all.
2. affinity; relationship
   Srpski i ruski su u bliskom srodstvu. — Serbian and Russian are closely related.
   Osećam neko duhovno srodstvo sa njim. — I feel a kind of spiritual affinity with him.

Often used in biti u srodstvu (sa kim) — "to be related (to someone)".