1.NounA single, distinctive rock formation; an area having a preponderance of a particular rock or group of rocks.
2.NounAn area of land or its particular features.
"The race will be run over a variety of terrain, including grass and sand."
3.NounThe surface of the earth; the ground.
"This approach requires the aircraft to stay at an altitude of at least 3000 feet MSL until crossing the VOR in order to maintain terrain clearance.; controlled flight into terrain; TOO LOW, TERRAIN"