A glen is a narrow valley, especially one nestled between hills or mountains. Picture a peaceful hollow where a stream might wind through grassy slopes, with trees clustering along the water and steep sides rising on either side. Glens are typically smaller and more intimate than wide valleys like the Grand Canyon.

Glen Coe in Scotland is one of the most dramatic, with towering mountains flanking a deep valley floor. Many Scottish place names include “glen”: Glencoe, Glenfiddich, Glendale.

In classic adventure stories like Treasure Island or tales of the Scottish Highlands, characters often travel through glens, using these natural passages through otherwise rugged terrain. Today, the word appears in poetry and place names across English-speaking countries, and it still carries that hint of misty Scottish hillsides and hidden valleys waiting to be explored.