| butte | a raised, flat area of land with steep cliffs;smaller than a mesa |
| desert | dry area with few plants; receives less than 10 inches of rain a year |
| flood plain | flat land near the edges of rivers formed by mud and silt deposited by floods |
| glacier | a large, slow-moving river of ice |
| mountain pass | a gap between mountains |
| oasis | a fertile spot in the desert fed by wells or underground springs |
| plain | a broad, level area of land |
| savanna | region with scattered trees and grassland |
| tributary | a stream or river that flows into a larger river |
| valley | low land between mountains or hills |
| current | the swiftest part of any moving body of water |
| lagoon | shallow body of water partly cut off from the sea |
| reservoir | a place where water is kept |