'Offspring' in the Bible

“Teacher, Moses wrote for us that if a man’s brother dies and leaves behind a wife and leaves no child, his brother should marry the wife and raise up children to his brother.

There were seven brothers; and the first took a wife, and died leaving no children.

The second one married her, and died leaving behind no children; and the third likewise;

and so all seven left no children. Last of all the woman died also.