The prison allowed him a three-day furlough during Christmas.

furlough 是名词，指"（军人、囚犯等的）短期休假"，特指获准暂时离开监狱或军队的许可。这个词源自荷兰语 "verlof"，意思是"许可、休假"。在美式英语中常用来指军人的休假或犯人的临时释放。