The Vietnamese word "dọng" primarily refers to the "back" or "spine" of a knife or sword. It is an important part of these tools, as it is the opposite edge of the blade that is generally not used for cutting.
In more advanced discussions, "dọng" can also be used metaphorically to describe something that is solid or reliable in other contexts, not just in reference to knives or swords.
While "dọng" is primarily used to refer to the back of a knife or sword, it may also be used in some contexts to refer to the spine of other elongated objects, though this is less common.