Alter Aeon Online Help

Keywords are:  'terrain'

The 'terrain' command indicates what type the local terrain is.  It can
be light forest, a mountain, a building, a cave or even underground.

Although a room's terrain can typically be extrapolated from its long
description, this command exists to remove any doubt.  It can be important to
know what the local terrain is because certain spells only work in certain
terrains. Also, certain types of resources are only available in certain
terrains. For example, you're not very likely to gather mesquite wood in
a swamp, or to gather water lilies in a desert.