summons, in law, document issued by a court ordering a specific person to appear at a specific time for some specific purpose. It is issued either directly to the person or to a law officer who must carry out the instructions. Often the purpose of a citation or summons is to require a person to answer charges or a complaint filed against him. It may also be used simply to notify a person that he has an interest in the proceedings at hand, which it would be to his advantage to attend.