Shān gōu (mountain ravine) refers to a narrow, deep valley or gully carved by water flow between mountains or hills. The character 山 means 'mountain', and 沟 means 'ditch', 'ravine', or 'gully' — together they literally denote a ditch-like depression in mountainous terrain. Unlike broader terms like 山谷 (shān gǔ, 'mountain valley'), 山沟 emphasizes narrowness, ruggedness, and often relative isolation.

This word commonly appears in geographical descriptions, travel writing, and historical or literary contexts — especially when evoking rural, remote, or underdeveloped mountain areas. It may carry subtle connotations of backwardness or seclusion (e.g., 'a far-off mountain ravine'), but it is neutral in scientific or topographic usage. It’s frequently used in northern China to describe actual landforms and also appears idiomatically in phrases like '山沟里飞出金凤凰' ('a golden phoenix flies out of the mountain ravine'), symbolizing unexpected success from humble origins.