In law in the United States, a praecipe is a document that either (A) commands a defendant to appear and show cause why an act or thing should not be done; or (B) requests the clerk of court to issue a writ and to specify its contents. In Canada it is used in place of a notice of motion as an application for a desk order that is granted in the court registry without a hearing before a judge.
However in the United States Clerks are variously limited to handle minor precepts (typical status adjustments) in the name of the Court (i.e., a Clerk cannot issue any forceful or mandamus writ).
The word praecipe is base Latin. The word survived long after the Roman Empire and found its way into England, where it survived in the English law. The writ was often issued to amend or change a subsequent order or to correct an error that may have been missed earlier. Its appearance in American law is not surprising, as many of the English customs and traditions were passed on. Today its function has barely changed since those days of Roman times.