A ravine is a landform that is narrower than a canyon and is often the product of streambank erosion.^[1] Ravines are typically classified as larger in scale than gullies, although smaller than valleys.^[1] Ravines may also be called a cleuch, dell, ghout (Nevis), gill or ghyll, glen, gorge, kloof (South Africa), and chine (Isle of Wight)

A ravine is generally a fluvial slope landform of relatively steep (cross-sectional) sides, on the order of twenty to seventy percent in gradient. Ravines may or may not have active streams flowing along the downslope channel which originally formed them; moreover, often they are characterized by intermittent streams, since their geographic scale may not be sufficiently large to support a perennial stream.^[2]

The shield volcanoes of Hawaii have significant impact on the distribution of ravines across the islands, specifically Mauna Loa and Mauna Kea, the former of which is one the most active shield volcanoes on Earth.^[3] Both of these volcanoes show V-shaped ravines on their flanks, solely where they have been mantled by Pahala ash. Being the older of the two, Mauna Kea displays more pronounced dissection of these ravines. Rainfall and infiltration capacity are critical to valley initiation on the Hawaiian volcanoes. Once these valleys are initiated, their streams incise to form V-shaped ravines. Eventually, they become sufficiently deep ravine systems and expose groundwater activity. The deepest of these incisions are U-shaped, theatre-headed valleys.^[4]