Which of the following is NOT one of the five major terrain features?

The correct choice indicates that "Canyon" is not one of the five major terrain features. The five major terrain features typically recognized in military and geological contexts include hill, valley, ridge, depression, and plain. Hills are elevated areas, valleys are low areas between hills or mountains, ridges are long, narrow elevations of land, and depressions are lower areas that can include basins or pits.

Canyons, while significant geological formations, do not fit into the primary categories established as major terrain features. A canyon is specifically a deep valley with steep sides, often carved by a river, which is more specific in nature and does not encompass the broader categories necessary to qualify as one of the five major terrain features. Thus, the identification of "Canyon" as the option that is not included in the standard list is accurate.