means A place where flowing water drops sharply over a ledge or cliff, falling more or less straight down.

from A plain English compound, old and unpretentious: 'water' (Old English wæter, from a deep Germanic root shared with Dutch water and German Wasser, all reaching back to a Proto-Indo-European source) plus 'fall' (Old English feallan, 'to drop'). Two everyday words bolted together to name an everyday wonder — the language simply described what it saw: water, falling.