Zera Yisrael (Hebrew: זרע ישראל, [zeˈra jisraˈʔel], meaning "Seed [of] Israel") is a legal category in halakha, Jewish religious law, that denotes the blood descendants of Jews who, for one reason or another, are not legally Jewish according to religious criteria.
References
Zera Yisrael Wikipedia(Text) CC BY-SA