A climbing enthusiast who attempts to reach the summit of all fifteen peaks above 14,000 feet in a particular region, often referring to Colorado mountains.
From fifteen (the number) plus -er (one who does). The term gained popularity in 20th-century mountaineering communities, especially in the American West.
Fifteeners became a cultural phenomenon in Colorado—climbing all 53 official 14,000-foot peaks is such a specific goal that an entire community formed around it.
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