A mesa is a flat-topped mountain or hill. It is a wide, flat, elevated landform with steep sides.
Mesa is a Spanish word that means table. Spanish explorers of the American southwest, where many mesas are found, used the word because the tops of mesas look like the tops of tables.
Mesas are formed by erosion, when water washes smaller and softer types of rocks away from the top of a hill. The strong, durable rock that remains on top of a mesa is called caprock. A mesa is usually wider than it is tall.
Mesas are usually found in dry regions where rock layers are horizontal. The Grand Mesa in the U.S. state of Colorado, considered the largest mesa in the world, has an area of about 1,300 square kilometers (500 square miles) and stretches for 64 kilometers (40 miles).