The words guides, geologists and park signs use about waterfalls, in plain English. Terms link through to the pages that go deeper.
- Block waterfall
- A waterfall that falls from a wide stream or river as one broad sheet, usually wider than it is tall. More →
- Caprock
- The hard layer of rock at the lip of a waterfall that resists erosion while softer rock beneath it is worn away. More →
- Cascade
- Water descending a series of rock steps or a steep slope while staying in contact with the rock, rather than falling free. More →
- Cataract
- A large, powerful waterfall or a stretch of violent rapids on a big river — the word stresses volume and force rather than height. More →
- Crest
- The top edge of a waterfall where water goes over; crest length is how a fall's width is usually measured.
- Discharge
- The volume of water passing a point per unit of time, usually given in cubic metres per second (m³/s). The measure behind claims of the 'largest' or 'most powerful' waterfall.
- Fan waterfall
- A waterfall that spreads out horizontally as it descends while staying in contact with the rock. More →
- Gorge
- A narrow, steep-sided valley — often the trench a waterfall has cut as it retreats upstream.
- Hanging valley
- A tributary valley left high above a main valley that a glacier deepened; its stream now drops as a waterfall. Behind most of the tallest falls in Norway, Yosemite and New Zealand. More →
- Headward erosion
- The process by which a waterfall migrates upstream as its lip is undercut and collapses.
- Horsetail
- A waterfall that keeps some contact with the rock as it drops, often flaring into a shape like a horse's tail. More →
- Hydraulic
- A recirculating current at the base of a waterfall or weir that can pull swimmers under and back toward the falling water. The main reason swimming close to the falls is dangerous. More →
- Knickpoint
- A sharp change in the slope of a river's bed. A waterfall is the most dramatic kind.
- Moonbow
- A rainbow formed by moonlight in spray or rain, usually seen near a full moon. Appears white to the naked eye. More →
- Plunge
- A waterfall in which water loses contact with the rock and falls free through the air. More →
- Plunge pool
- The basin scoured at the foot of a waterfall by falling water and the rock it carries.
- Punchbowl
- A waterfall in which the water is squeezed through a narrow gap before spreading into a wide pool below.
- Segmented waterfall
- A waterfall that splits into two or more separate streams side by side as it descends. More →
- Spray zone
- The area around a waterfall kept permanently wet by mist, often with its own microclimate — at Victoria Falls, a strip of rainforest.
- Tepui
- A flat-topped, sheer-sided sandstone mountain of the Guiana Highlands in Venezuela, Guyana and Brazil. Angel Falls and Kaieteur drop from the edges of these plateaus. More →
- Tiered waterfall
- A waterfall that descends in a series of distinct drops, each with its own ledge or pool. More →
- Travertine
- Limestone deposited from mineral-rich water. Travertine and its porous form, tufa, build the terraces and blue pools at places such as Plitvice, Havasu and Kuang Si. More →
- Tufa
- A soft, porous form of calcium carbonate deposited by water with the help of mosses and algae. Tufa barriers dam the lakes at Plitvice and Krka.
- Undercutting
- Erosion of soft rock beneath a harder layer at a waterfall, leaving an overhang that eventually collapses.
- Water level (low / high water)
- How much is flowing over a fall at a given time of year. High water means more spectacle and spray; low water often opens pools, rafting runs and access that high water closes. More →
- Whitewater grade
- The international scale for river difficulty, from Grade I (easy) to Grade VI (unrunnable). Commercial rafting below Victoria Falls runs Grade IV–V. More →