#plain__champaign  extensive tract of level open land; "they emerged from the woods onto a vast open plain"; "he longed for the fields of his youth"
  supertype:  #dry_land__dryland__land__earth__solid_ground__solidground__terrafirma  the solid part of the earth's surface; "the plane turned away from the sea and moved back over land"; "the earth shook for several minutes"; "he dropped the logs on the ground"
  instance:  #Olympia
  subtype:  #flat  a level tract of land
     subtype:  #salt_flat__salt_plain  a flat expanse of salt left by the evaporation of a body of salt water
  subtype:  #llano  an extensive grassy and nearly treeless plain (especially in Latin America)
  subtype:  #moor__moorland  open land usually with peaty soil covered with heather and bracken and moss
  subtype:  #snowfield  a permanent wide expanse of snow
  subtype:  #steppe  extensive plain without trees (associated with eastern Russia and Siberia)
  subtype:  #tundra  a vast treeless plain in the arctic regions between the ice cap and the tree line

No statement uses or specializes #plain; click here to add one.