Buttes are geological formations that have steep sides and either narrow, pointed or small, flat tops. They are the water or wind eroded remains of mesas, which are formations hundreds of feet in height, with wide, flat tops. Early Southwestern settlers colloquially differentiate mesas and buttes by their capacity to sustain cattle. If there is water nearby and you could allow cattle to graze, it's a mesa. Geographers on the other hand define mesas as formations or hills having tops wider than their height.