Final answer:
The term 'cover' generally means protection or concealment from danger or observation. In wartime, it involved precautions like hiding safely and concealing lights to prevent detection by enemies. Cover may also refer to materials that can stop bullets for physical protection.
Step-by-step explanation:
The term cover refers to something that conceals or protects an individual or object from observation or danger. In a historical context, especially during wars, it could mean making sure that people were hiding safely and taking measures to prevent detection by enemy forces, such as covering up any light that might help an enemy aircraft target civilian populations. This kind of cover would not necessarily stop bullets but would provide concealment. In a military context, however, cover can also refer to materials or objects that can stop, impede, or alter the flight of a bullet, providing both concealment and protection against firearms.