in Law, a judicial writ which lies in cases where the jury being impanelled and returned before the justices of the bank, one of the parties requests to have such a writ for the ease of the country, in order that the trial may come 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 impanelled, at a certain day, before the justices, "nisi prius justiciarii domini regis ad quas capiendas venerint."