A lapiaz is an area of limestone formation that resembles naturally gullies, crevices and drain-aways, a distinctive rock-formation as a result of erroded limestone blocks, called clints, which are dissected by fissures, or grikes/grykes.  It is a distinctive eroded surface with characteristic of karst morphology (created from the dissolution of soluble rocks). The term comes from Karst, a region in Slovenia which gave its name to this particular geological landscape feature.
Rainwater, charged with carbon dioxide, dissolves the limestone when it comes into contact with it. The rock becomes grooved, a few centimetres wide, separated by blades that can be sharp. The dissolved limestone is then carried downwards by the seeping water and can precipitate again, either in underground karstic areas (sink-holes, underground water-channels and chambers), leading to the creation of stalactites, or as natural water-springs, producing calcareous tuff rocks or travertine rocks. Here, erosion is still very active.

An almost "dwarfed" or stunted vegetation takes hold and grows in these rocky gaps and crevices. Oaks, juniper gorses, raspberry bushes, maples, lavender, ferns, lichens form rows of plant alignments that follow the the natural lines of rock erosion. Grey lizards love to zigzag across these sun-drenched limestone ridges.

The term lapiaz comes from the Latin word lapis, which means "stone".