The prisoner has been on death-row for fifteen years.

death-row 是由 death（死亡）和 row（排、行）组成的复合名词，字面意思是"死亡之列"。 death-row 指监狱中专门关押等待执行死刑的囚犯的区域，即"死囚区"或"死刑犯监区"。