A German word derived from Kras, the Serbo-Croat name for a region of rugged limestone plateaus in the Dinaric Alps near the Adriatic coast of Croatia, karst refers to limestone areas riddled with extensive subterranean streams and caves, and an aboveground terrain that collapses into these underground channels, leaving distinctive hollows, pits, and sinkholes. This kind of landscape typically develops in humid uplands (such as southern Indiana, Florida, and Kentucky) where thick, strongly jointed limestone underlies the soil and abundant rainfall provides water to drive the carbonate-solution process that generates caves.

Barbara Kingsolver