help > terrains
Terrains indicate what the environment in the room is like, whether
it's a flat plain or rugged mountains, heavy forest or deep underwater.
There are a number of possible terrain types, and there can be many
in a particular room (an underground pool, for instance, or a road in
the middle of a jungle).

Most races have combat modifiers based on the local terrain. This
represents the race's comfort level in a particular terrain, and its
ability to use the terrain to its benefit. A positive modifier means
you will deal more damage in normal combat, while a negative modifier
means you will deal less.

You can check the local terrains with the 'terrain' or 'realm' commands.

See also:  terrainlist, terrain, realm