Definitions for ventifactˈvɛn təˌfækt
Random House Webster's College Dictionary
a pebble or cobble that has been faceted, grooved, and polished by the erosive action of wind-driven sand.
Origin of ventifact:
1911; < L venti-, comb. form of ventuswind1+(arti)fact
A pebble or little stone shaped and polished by wind-blown sand.