Usage Note: Though prior usually modifies a noun that comes after it, as in prior approval, it sometimes modifies a noun for a unit of time which precedes it, as in five years prior. These constructions are marginally acceptable when the combination serves as the object of a preposition, as in A gallon of gasoline was $4.29, up 10 cents from the week prior. In our 2014 survey, 51 percent of the Panelists accepted the sentence, with many commenting that they would prefer from the prior week or from the week before. The construction is even less acceptable when it acts as an adverbial modifier: only 29 percent of the Panel approved My cell phone was stolen. I had just bought it two days prior.