quominus

Noun

 * 1)  A writ and legal fiction that (until the late 19th century) allowed the Court of Exchequer to obtain a jurisdiction over cases normally brought in the Court of Common Pleas, based on having the plaintiff in a debt case claim that he was a debtor to the king, and that the defendant's debt prevented him paying the king.

Etymology
From instrumental +.

Conjunction

 * 1) that not