Wiktionary
n. (context legal English) In adversarial legal systems, a statement made by either party at the beginning of a trial or comparable factfinding proceeding, in which that party lays out their case, generally including the points of fact that they intend to demonstrate and to some degree indicating the rhetorical arguments for why they should prevail.
Usage examples of "opening argument".
So instead of working on my opening argument for Random, I spent the next hour or so considering the nature of a being capable of moving into a person and taking over the controls.
Lee took the entire rest of the morning for his opening argument, which seemed shut pretty tight to me.
Bishop de Clinton opened the session by welcoming all comers in goodwill to the house of which he was titular abbot as well as bishop, and asserting, as he had promised, the ban on the carrying of weapons either here in hall, or, under any circumstances, when attending the office of the Church, then he handed over the opening argument to Henry of Blois, King Stephen's younger brother and bishop of Winchester.
Bishop de Clinton opened the session by welcoming all comers in goodwill to the house of which he was titular abbot as well as bishop, and asserting, as he had promised, the ban on the carrying of weapons either here in hall, or, under any circumstances, when attending the office of the Church, then he handed over the opening argument to Henry of Blois, King Stephens younger brother and bishop of Winchester.
It was a summary, not an opening argument, but before Ibryen could say anything he was once again the focus of Rachyl’.
I was going to give her an opening argument anyway and raised my hand to make her listen.