1 The reason or reasons offered for or against something. 2 The formal oral or written presentation of such reasons intended to convince or persuade. 3 The section of an appellate or trial brief in which a party presents its interpretation of the law. argumentative closing argument.At a trial, the final statement given by the parties or their attorneys to the judge or jury, before deliberation, in which they summarize the evidence and the applicable law, present their interpretation of the sa...