terrain
Pluralterrains (some meanings)
- 1A stretch of land, or the physical features that give a particular area its character.
The race route covered varied terrain, from sandy flats to steep rocky climbs.
Engineers studied the surrounding terrain before deciding where to route the new road.
Similarground, landscape, country, land, topography
Note
The everyday sense describes the lie of the land, its slopes, sand, grass and rock, rather than the geologist's rock units. It usually behaves as a mass noun, as in varied terrain or a variety of terrain, with no article. The countable form, a difficult terrain or two terrains, appears when one distinct stretch of land is set against another.
- 2The surface of the earth; the ground beneath.
The onboard radar maps the terrain so the crew can avoid mountains in poor visibility.
At low altitude the system follows the terrain, climbing and descending with the hills below.
Note
For pilots and their instruments, this is the ground considered as something an aircraft can hit. It appears in fixed phrases such as terrain clearance, controlled flight into terrain and the cockpit alert "TOO LOW, TERRAIN". In this register it is uncountable and usually bare. What matters is not what the land looks like, as in the everyday landscape sense, but how far below the aircraft it lies.
Investigators classified the accident as controlled flight into terrain.
The crew climbed at once when the alert called "TOO LOW, TERRAIN."
- 3A single distinctive rock formation, or an area dominated by one particular rock type or group of rocks.
The survey identified a limestone terrain cut through by ancient riverbeds.
Mappers carefully distinguished the basaltic terrain from the sedimentary layers around it.
Similarformation
Note
The geologist's use sorts ground by what it is made of. A terrain here is a mappable unit defined by its shared rock character, so a limestone terrain or a basaltic terrain names the stone rather than the scenery. It is countable when such units are mapped side by side. The word came through French from Latin terrenum, built on terra, "earth".
Practice
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Origin
A direct borrowing from French terrain, which came from Latin terrenum ('land, ground'), the neuter of terrenus ('consisting of earth'), from terra ('earth').