'Threshold' in the Bible

In those days, while Mordecai sat in the king's gate, two of the king's chamberlains, Bigthan and Teresh, of those which kept the threshold, were wroth, and sought to lay hand on the king Ahasuerus.

And it was found written, that Mordecai had told of Bigthana and Teresh, two of the king's chamberlains, keepers of the threshold, who had sought to lay hand on king Ahasuerus.