Definition - What does Oral Argument mean?
An oral argument is a defense that is made verbally in court by the legal team of either the plaintiff or the defendant. The defense would be giving an oral argument against why the facts presented by the plaintiff are incorrect, and the plaintiff's legal team would make an oral argument as to why they are right.
Justipedia explains Oral Argument
The arguments are made orally for the benefit of the judge and all parties. The judge rules on the case after hearing and considering the oral arguments put forth by both sides.