fourteener在文中指的是高度超过14000英尺的山峰（美国方言）。可以参考柯林斯英语词典的解释。US dialect
a mountain that is higher than 14,000 feet
As a fourteener, and one of the easiest to climb of the 54 over 14,000 feet, it attracts a large number of hikers seeking one of Colorado's peak experiences.