His short story was one of the winning entrys in the national competition.

entry 是名词，意思是"参赛作品"或"参赛项目"。这里用复数形式 entries 表示"多个参赛作品"。 winning entries 指"获奖的参赛作品"，winning 是形容词，表示"获胜的、获奖的"。