in Law, a judicial writ which lies in cases where, the jury being impaneled and returned before the justices of the bank, one of the parties requests to have such a writ for the case of the county, that the trial may take place before the justices in the same county on their coming thither. The purport of a writ of nisi prius is, that the sheriff is thereby commanded to bring to Westminster the men impaneled, at a certain day, before the justices, nisi prius justiciarii domini regis ad assisas capendas venirent.