'Seed' in the Bible

The king spoke to Ashpenaz the master of his eunuchs, that he should bring in [certain] of the children of Israel, even of the seed royal and of the nobles;

Whereas you saw the iron mixed with miry clay, they shall mingle themselves with the seed of men; but they shall not cling to one another, even as iron does not mingle with clay.

In the first year of Darius the son of Ahasuerus, of the seed of the Medes, who was made king over the realm of the Chaldeans,